HIGH-EXPLOSIVE  SHELL 
MANUFACTURE 


HIGH-EXPLOSIVE  SHELL 
MANUFACTURE 


A  COMPREHENSIVE  TREATISE  ON  THE  FORGING, 
MACHINING  AND  HEAT-TREATMENT  OF  HIGH-EX- 
,  PLOSIVE  SHELLS  AND  THE  MANUFACTURE  OF 
CARTRIDGE  CASES,  PRIMERS,  AND  FUSES,  GIVING 
COMPLETE  DIRECTIONS  FOR  TOOL  EQUIPMENT 
AND  METHODS  OF  SETTING  UP  MACHINES, 
TOGETHER  WITH  A  REVIEW  OF  THE  MAKING  OF 
POWDERS,  HIGH  EXPLOSIVES,  AND  FULMINATES 


By  DOUGLAS  T.  HAMILTON 

ASSOCIATE  EDITOR  OF  MACHINERY 

AUTHOR  OF  "ADVANCED  GRINDING  PRACTICE," 

"AUTOMATIC  SCREW  MACHINE  PRACTICE," 

"SHRAPNEL  SHELL  MANUFACTURE," 

"CARTRIDGE  MANUFACTURE,"  ETC. 


FIRST  EDITION 


NEW  YORK 

THE   INDUSTRIAL  PRESS 

LONDON:  THE  MACHINERY  PUBLISHING  CO.,  LTD. 

1916 


COPYRIGHT,  1916 

BY 

THE  INDUSTRIAL  PRESS 
NEW  YORK 


PREFACE 


The  manufacture  of  high-explosive  shells  has,  within  the 
past  year,  become  one  of  the  most  important  of  the 
mechanical  industries  in  this  country,  and  the  design  of 
these  shells  and  the  machining  of  their  component  parts  are 
now  of  the  greatest  interest  to  a  large  number  of  manufac- 
turers, designers,  toolmakers,  and  mechanics  in  general. 
Machine  tool  builders  have  been  called  upon  to  provide  tools 
and  devices  of  standard  and  special  design  to  meet  the 
demand  for  rapid  and  accurate  production.  As  a  result, 
there  has  been  a  remarkable  development  in  the  tool  equip- 
ment, and  in  the  methods  used  in  the  forging  and  machin- 
ing of  shells.  The  larger  sizes  of  high-explosive  shells  are 
made  mainly  from  forgings,  while  the  smaller  sizes  are 
made  from  bar  stock.  The  forged  shell  blanks  are  made  by 
means  of  hydraulic  forging  presses,  bulldozers  or  special 
forging  machines  that  have  been  developed  primarily  for 
this  class  of  work.  When  made  from  bar  stock,  high- 
powered  drilling  machines  or  similar  machines  of  special 
construction  are  used.  Great  developments  have  taken  place 
in  regard  to  the  machines  suitable  for  high-power  drilling. 

This  book,  which  is  a  companion  volume  of  the  treatise 
already  published  on  "Shrapnel  Manufacture,"  has  been 
brought  out  to  meet  the  demand  for  a  comprehensive  book 
dealing  with  the  construction,  forging,  machining,  heat- 
treatment,  inspection,  and  testing  of  high-explosive  shells. 
It  covers  completely  the  methods  of  machining  these  shells 
when  made  either  from  bar  stock  or  from  forged  blanks.  In 
addition,  the  manufacture  of  high-explosive  or  detonating 
fuses,  cartridge  cases,  primers,  etc.,  is  dealt  with  in  detail. 
In  the  book  is  included  all  the  material  on  the  subject  pub- 
lished during  the  past  year  in  MACHINERY,  supplemented  by 
other  material  wherever  necessary  to  complete  the  treatise. 

The  different  classes  of  powder,  high-explosives,  and 
fulminates  have  also  been  described,  and  a  brief  outline  is 

338017 


given  of  their  manufacture.  An  endeavor  has  also  been 
made  to  indicate  the  difficulties  that  manufacturers  have 
met  with  in  the  making  of  high-explosive  shells.  Due  to  the 
fact  that  the  information  given  is  very  complete  and  covers 
all  the  different  phases  of  the  work,  it  is  believed  that  the 
book  will  prove  a  valuable  companion  volume  to  those 
already  brought  out  by  the  Publishers  of  MACHINERY  on  the 
manufacture  of  munitions. 

D.  T.  H. 
New  York,  January,  1916. 


CONTENTS 

PAGES 

CHAPTER  I. 

High-explosive      and      Armor-piercing 

Shells   : 1-31 

CHAPTER  II. 

Explosives,  Detonators  and  Fulminates .         32-41 

CHAPTER  III. 

Forging  High-explosive  Shells 42-52 

CHAPTER  IV. 

Machining  British  18-pound  Shells 53-79 

CHAPTER  V. 

Machining  Russian  and  Serbian  Shells.         80-99 

CHAPTER  VI. 

Machining  French  120-millimeter  (4.72- 
inch)    Shells    100-126 

CHAPTER  VII. 

Machining  British  Howitzer  Shells 127-144 

CHAPTER  VIII. 

Miscellaneous    Tools    and    Devices    for 

Shell  Manufacture 145-162 

CHAPTER  IX. 

British  High-explosive  Detonating  Fuse     163-180 

CHAPTER  X. 

High-explosive    Cartridge    Case    Manu- 
facture       181-211 

CHAPTER  XL 

Making    Cases    with    Bulldozers    and 

Planers   212-224 

CHAPTER  XII. 

Cost  of  Munitions  of  War.  .  225-227 


HIGH-EXPLOSIVE  SHELL 
MANUFACTURE 


CHAPTER  I 
HIGH-EXPLOSIVE  AND  ARMOR-PIERCING  SHELLS 

THE  common  high-explosive  shell  which  is  used  chiefly 
for  the  destruction  of  fortifications  did  not  come  into  gen- 
eral use  until  the  latter  part  of  the  sixteenth  century. 
About  that  time,  hollow  balls  of  cast  iron  were  filled  partly 
with  black  gunpowder  and  partly  with  a  slow-burning  com- 
position that  was  ignited  by  several  different  types  of  fuses. 
These  shells  did  not  give  very  satisfactory  results.  An  im- 
provement was  made  by  fitting  into  the  shell  a  hollow  forged 
iron  or  copper  plug  filled  with  slow-burning  powder.  Until 
about  1871,  the  shells  were  spherical  in  shape  and  were  fired 
from  smooth-bored  guns  (not  rifled). 

Development  of  High-explosive  Shells.  —  Upon  the  ad- 
vent of  the  rifled  gun,  sabots,  as  shown  in  Fig.  1,  were  fas- 
tened to  the  base  of  the  spherical  shell  and  took  the  rifling 
grooves  in  the  gun.  These  were  usually  made  of  wood  and 
the  rim  was  covered  with  sheet  iron,  steel,  or  copper.  When 
the  first  types  of  high-explosive  shells  burst,  they  broke  into 
comparatively  large  pieces,  and  did  not  have  a  very  destruc- 
tive effect.  Later  developments  consisted  in  making  the 
shells  from  cast  or  forged  steel  and  filling  them  with  high- 
explosives  such  as  lyddite,  melenite,  shimose,  etc.,  instead 
of  common  black  gunpowder.  These  shells  were  sometimes 
cast  in  sand  molds,  head  downwards,  from  steel  of  the 
proper  composition  to  give  the  required  strength.  They 
were  then  annealed  by  being  left  in  a  furnace  until  brought 
to  a  red  heat,  when  they  were  removed  and  allowed  to  cool 
gradually  in  the  air.  The  interior  of  the  cast  shell  was 
seldom  machined,  except  at  the  base  end  for  the  insertion 


2  HIGH-EXPLOSIVE  SHELLS 

of  the  base  fuse,  and  the  exterior  was  ground  or  finished 
in  a  lathe  and  grooved  at  the  base  end  to  form  a  seat  for 
the  rotating  band. 

Types  of  High-explosive  Shells. —  There  are  in  use  at  the 
present  time  four  types  of  shells  that  may  be  said  to  be 
high-explosive.  The  first,  but  not  the  most  common,  is 
known  as  the  high-explosive  shrapnel  shell.  This  type  of 
projectile,  shown  at  A,  Fig.  2,  combines  the  principles  of 
both  the  high-explosive  shell  and  the  common  shrapnel 
shell,  and  has  been  used  by  some  governments  within  the 


SLOW-BURNING 
MATERIAL 


Machinery 


Fig.  1.     Original  Cast-iron  Spherical   High-explosive  Shell 

past  four  or  five  years.  In  this  shell,  the  head  or  fuse  car- 
ries a  high-explosive  charge  and  the  matrix  surrounding 
the  bullets  is  a  high-explosive  material  capable  of  being  de- 
tonated by  the  detonation  of  the  fuse.  This  projectile  car- 
ries a  combination  time  and  percussion  fuse  and  a  base 
charge  of  black  powder  similar  to  the  common  shrapnel. 
For  use  as  a  common  shrapnel,  the  fuse  and  bullets  are  ex- 
pelled without  any  detonation,  the  matrix  serving  to  pro- 
duce smoke  as  in  the  common  shrapnel.  The  head  or  fuse 


HIGH-EXPLOSIVE   SHELLS 


3 


4  HIGH-EXPLOSIVE   SHELLS 

continues  in  flight  and  detonates  upon  impact,  causing  con- 
siderable damage,  and  is  capable  of  destroying  the  shield 
used  in  protecting  a  field  gun.  In  the  event  that  the  fuse 
is  set  to  explode  upon  impact,  the  high-explosive  material 
in  the  head  and  the  matrix  in  the  shell  detonate  together, 
thus  giving  the  effect  of  a  high-explosive  shell.  The  explo- 
sive commonly  used  in  the  head  and  as  a  matrix  in  this 
class  of  ammunition  is  trinitrotoluol,  which  is  used  in  con- 
nection with  fulminate  of  mercury,  or  other  similar  mate- 
rials necessary  to  start  the  detonation.  Fig.  4  shows  the 
condition  of  one  of  these  shells  after  being  detonated  upon 
impact,  this  shell  not  having  filled  the  function  of  a  common 
shrapnel  shell.  The  projectile  shown  here  is  an  American 
3-inch  caliber,  high-explosive  shrapnel  weighing  15  pounds. 

Common  High-explosive  Shell.  —  The  shell  shown  at  B, 
Fig.  2,  is  known  as  a  common  high-explosive  shell,  and  is 
the  type  used  in  medium-caliber  field  guns  by  the  Russian 
government.  The  fuse  or  exploder  is  inserted  in  the  nose 
end  of  the  shell,  and  usually  surrounded  by  a  high-explosive 
— picric  acid,  lyddite,  melenite,  trinitrotoluol,  etc.  This 
shell  is  used  principally  against  fortifications,  although  it 
can  be  used  to  some  extent  for  field  operations.  It  explodes 
upon  impact  and  possesses  enormous  destructive  power. 
Some  idea  of  the  great  damage  wrought  by  a  modern  high- 
explosive  shell  will  be  obtained  by  referring  to  Fig.  5,  which 
shows  the  condition  of  an  American  3-inch  high-explosive 
shell  after  bursting.  The  fragments  were  obtained  by  ex- 
ploding the  shell  in  an  enclosed  sand  pit. 

Delay-action  Fuse  Shells.  —  The  shell  shown  at  C,  Fig.  2, 
is  used  in  coast  defense  and  field  guns  and  carries  a  fuse 
located  in  the  base.  When  used  by  the  American  govern- 
ment in  field  guns,  it  is  equipped  with  a  delay-action  fuse  and 
carries  from  3  to  30  per  cent  of  its  weight  of  high-explosive. 
The  lighter  charged  shells  are  used  for  repelling  infantry 
attacks,  whereas,  the  heavier  charged  shells  are  used  for 
destroying  fortifications.  One  of  these  types  is  used  as  an 
armor-piercing  shell;  this  contains  a  very  large  bursting 
charge  and  is  furnished  with  a  quick-acting  fuse.  It  is  used 
principally  to  repel  attacks  of  light-armored  vessels  or  for 


HIGH-EXPLOSIVE   SHELLS  5 

attacking  the  upper  works  of  heavily-armored  ships.  It  ac- 
complishes its  purpose  by  exploding  upon  impact,  driving 
in  the  thin  plates  and  destroying  those  parts  not  protected 
by  heavy  armor. 

The  type  of  shell  shown  at  D  is  also  known  as  an  armor- 
piercing  shell.  This  carries  a  much  lighter  explosive  charge 
than  the  shell  shown  at  C,  and  is  made  with  much  thicker 
walls.  This  shell  carries  a  delay-action  fuse,  which  per- 
mits the  projectile  to  pass  through  the  armor  plate  and  into 
the  interior  of  the  vessel  before  exploding. 

Construction  of  Modern  High-explosive  Shells.  —  High- 
explosive  shells  are  made  at  present  in  a  variety  of  shapes 
and  sizes,  ranging  all  the  way  from  1.4  to  16  inches  in  diam- 
eter and  from  1  to  2400  pounds  in  weight.  The  shells  used 
by  various  governments  also  differ  considerably  in  construc- 
tion. For  instance,  the  American  government  uses  a  solid- 
point  nose  shell  as  shown  at  A,  Fig.  3,  which  is  almost  the 
same  in  construction  as  the  armor-piercing  shell  and  can  be 
used  against  light-armored  cruisers  or  the  upper  works  of 
heavily-armored  ships.  The  shell  is  provided  with  a  rifling 
band  near  the  base  and  also  with  an  inserted  bronze  plug 
in  which  the  base  type  of  fuse  is  held.  The  type  of  fuse 
used  varies  with  the  use  to  be  made  of  the  shell.  For  in- 
stance, in  mountain  guns,  howitzers,  and  mortars,  a  centri- 
fugal type  of  fuse,  as  shown,  is  generally  used ;  whereas,  for 
high-velocity  field  guns,  a  ring-resistance  fuse  is  generally 
employed.  The  cartridge  case  and  primer  held  in  the  base 
are  similar  in  construction  to  those  used  on  shrapnel  shells. 
This  type  of  high-explosive  shell  explodes  upon  impact  only 
and  the  cavity  is  filled  with  an  explosive  called  explosive 
"D"  from  its  inventor  Lieut.-Col.  B.  W.  Dunn;  it  is  also 
sometimes  known  as  "dunnite."  Dunnite  is  not  a  sensitive 
explosive ;  consequently,  quite  a  heavy  detonating  charge  is 
used.  The  detonating  composition  is  made  of  picric  acid 
in  various  portions  or  T.  N.  T.  (trinitrotoluol). 

British  18-pounder  Shell.  —  The  British  18-pounder  high- 
explosive  shell  is  shown  at  B,  Fig.  3.  This  shell  is  provided 
with  very  thick  walls  and  carries  a  charge  of  high-explosive, 
generally  lyddite.  A  nose  fuse  instead  of  a  base  fuse  is 


6 


HIGH-EXPLOSIVE   SHELLS 


AMERICAN  3-INCH 
A 


BRITISH  18-POUNDER  (3.29") 


FRENCH  75  M.M.(2.95") 

c 


RUSSIAN  3-INCH 

D 


Fig.  3.     Types  of  High-explosive  Shells  used   by  American,   British,   French, 
and  Russian  Governments 


HIGH-EXPLOSIVE  SHELLS  7 

used  and  the  fuse  operates  on  percussion  only.  In  order  that 
the  lyddite  will  be  satisfactorily  detonated,  the  fuse  has  an 
extension  known  as  a  gaine,  which  continues  into  the  cavity 
of  the  shell  for  quite  a  distance.  This  gaine  is  filled  with 
three  different  detonating  materials,  each  successive  one 
being  more  powerful  than  the  last.  In  other  words,  this 
shell  is  set  off  by  what  is  known  as  the  delay-action  fuse. 
This  allows  the  shell  to  penetrate  fortifications  or  earth- 
works before  it  is  detonated,  and,  consequently,  enables  the 
explosion  to  have  a  much  more  destructive  effect  than  if 
it  took  place  instantaneously  upon  impact.  This  particular 
size  of  high-explosive  shell  is  generally  made  from  bar  stock 
and,  in  order  to  avoid  chances  of  piping,  a  gas  plug  is  in- 
serted in  the  base  of  the  shell,  as  shown.  The  cartridge 
case  and  primer  held  in  the  base  are  the  same  as  those  used 
on  the  shrapnel  shell. 

French  75-millimeter  Shell. — The  now  famous  French 
75-millimeter  high-explosive  shell  is  shown  at  C,  Fig.  3. 
This  shell  is  made  from  a  forging  having  comparatively 
thin  walls,  and  is  hardened  and  heat-treated  to  increase  its 
elastic  limit  and  tensile  strength.  It  also  carries  in  the  nose 
a  delay-action  fuse  that  is  of  interesting 'construction.  The 
cavity  in  the  shell  is  generally  filled  with  a  high-explosive 
known  as  melenite,  the  base  of  which  is  picric  acid.  The 
melenite  is  poured  into  the  cavity  of  the  shell  while  in  a 
liquid  form  and  solidifies  upon  cooling.  The  exploder, 
shown  extending  from  the  end  of  the  fuse  into  the  explo- 
sive, is  filled  with  melenite  in  powder  form.  The  character- 
istics of  the  detonator  and  bursting  charge  have  to  be  simi- 
lar in  order  that  the  greatest  possible  shattering  effect  may 
be  produced.  The  fuse  used  in  this  shell  is  also  of  the  delay- 
action  type  and  enables  the  projectile  to  penetrate  earth- 
works or  fortifications  before  detonation  takes  place.  The 
cartridge  case  is  similar  to  that  used  on  the  shrapnel  shell 
and  is  filled  with  smokeless  powder  (nitrocellulose)  in  stick 
form. 

Russian  3-inch  Shell.  —  The  Russian  3-inch  high-explo- 
sive shell  is  shown  at  D,  Fig.  3.  The  shell  proper  is  made 
from  a  forging  that  is  heat-treated  before  or  after  machin- 


II 

0-w 


W  c 


ARMOR-PIERCING  SHELLS  9 

ing,  depending  on  the  practice  followed.  It  must  have  an 
elastic  limit  of  not  less  than  62,000  pounds  per  square  inch 
and  a  tensile  strength  of  118,000  pounds  per  square  inch. 
This  shell  also  carries  in  its  nose  a  detonating  fuse,  which, 
however,  differs  considerably  from  any  of  the  fuses  pre- 
viously illustrated.  This  fuse  is  practically  instantaneous 
and  detonates  the  high-explosive  material  in  the  shell  upon 
impact.  The  cartridge  case  carries  a  heavy  charge  of 
smokeless  powder — generally  nitrocellulose — and  also  a 
primer  in  the  base  end  somewhat  similar  in  construction  to 
that  used  in  the  British  shell.  This  projectile  has  a  muzzle 
velocity  of  over  1900  feet  per  second ;  and,  as  the  shell  proper 
is  heat-treated,  it  has  considerable  destructive  effect  when 
the  high-explosive  contained  within  it  is  detonated. 

Armor-piercing  Projectiles.  —  Following  the  introduction 
of  iron  sheathing  for  ships,  it  was  found  that  the  ordinary 
cast-iron  high-explosive  projectile  did  not  readily  pierce  the 
plate,  so  that  it  became  necessary  to  produce  a  projectile 
that  would  do  so.  This  was  accomplished  by  Sir  W.  Pal- 
liser,  who  invented  the  method  of  hardening  the  head  of  the 
pointed  cast-iron  shell  by  casting  the  projectile  point  down- 
wards and  forming  the  head  in  an  iron  mold ;  the  metal  at 
the  point  being  suddenly  chilled  became  intensely  hard, 
while  the  rest  of  the  casting  remained  comparatively  soft. 
The  casting  when  partly  cold  was  taken  out  of  the  mold 
and  thrown  down  into  the  sand,  where  it  was  allowed  to  cool 
off  gradually.  These  shells  proved  very  effective  against 
wrought-iron  armor,  but  had  little  effect  against  steel  armor 
plates.  An  improved  shell  was  then  devised  which  was 
made  from  forged  steel  with  a  point  hardened  so  as  to 
pierce  the  armor;  this  projectile  is  generally  formed  from 
steel  containing  both  nickel  and  chromium,  and  sometimes 
tungsten.  Armor-piercing  shells  are  generally  cast  from  a 
special  mixture  of  chrome-nickel  steel,  melted  in  a  crucible 
and  afterwards  forged  into  shape.  The  shell  is  then  thor- 
oughly annealed,  bored  internally,  and  turned  on  the  exte- 
rior in  a  lathe.  The  heat-treatment  consists  in  hardening 
the  head  of  the  projectile  and  tempering  it  in  such  a  man- 
ner that  the  rear  portion  is  reduced  in  hardness  so  as  to 


10 


ARMOR-PIERCING   SHELLS 


Fig.  5.     Condition  of  a  3-inch   American   Common    High-explosive  Shell   after 

passing  through  a  Steel   Plate  and  into  a  Bank  of  Sand,  and  after 

bursting.     (Annual    Report,  Smithsonian   Institution,  1914) 


ARMOR-PIERCING  SHELLS  11 

render  it  extremely  tough,  whereas,  the  point  is  extremely 
hard.  There  are  two  types  of  armor-piercing  shells :  One, 
known  as  a  shot,  is  used  for  piercing  armor  and  carries  a 
light  bursting  charge;  the  other,  known  as  a  shell,  carries 
a  much  heavier  bursting  charge,  is  longer,  has  thinner 
walls,  and  is  much  more  destructive. 

Capped  Projectiles.  —  As  shown  at  D,  Fig.  2,  the  armor- 
piercing  shell  is  similar  in  shape  to  the  common  high-explo- 
sive shell  shown  at  C,  with  the  exception  that  the  walls  are 
much  thicker  and  the  point  is  still  thicker..  In  order  to 
greatly  reduce  the  air  resistance  encountered  in  flight, 
armor-piercing  shells  are  provided  with  a  long  pointed  outer 
covering  for  the  head.  It  was  also  found  that  if  an  armor- 
piercing  shell  having  a  hardened  nose  struck  an  armor  plate 
with  great  force,  the  force  of  the  blow  shattered  the  head 
and  made  it  ineffective,  A  soft  steel  cap  placed  on  the  shell, 
supports  the  point  and  greatly  improves  the  chances  of  the 
projectile  getting  through  a  hard  armor  plate  unbroken. 
One  of  the  plausible  theories  advanced  as  to  the  ineffective- 
ness of  an  uncapped  head  is :  When  an  uncapped  projectile 
strikes  the  extremely  hard  face  of  a  modern  armor  plate, 
the  whole  energy  of  the  projectile  is  applied  at  the  point 
and  the  high  resistance  of  the  face  of  the  plate  puts  the 
very  small  arc  at  the  point  of  the  projectile  to  a  stress 
greater  than  the  metal  can  resist.  The  point  is  therefore 
broken  or  crushed  and  the  head  of  the  projectile  is  flattened ; 
this  greatly  reduces  the  penetrating  power  and  results  in 
the  point  of  the  projectile  being  practically  welded  to  the 
armor  plate.  When  a  capped  projectile  strikes  a  hard  plate, 
the  resistance  of  the  plate  is  distributed  over  a  greater  area, 
and  the  point  is  supported  by  the  cap.  Consequently,  the 
point  is  not  deformed  and  passes  through  the  plate. 

The  specifications  for  the  test  governing  the  manufacture 
of  armor-piercing  projectiles  are  very  stringent  and  re- 
quire that  the  shell  perforate  a  hard-face  armor  plate  as 
thick  as  the  caliber  of  the  projectile  without  breaking  the 
point.  In  other  words,  a  6-inch  projectile  is  required  to 
completely  pass  through  a  6-inch  armor  plate  in  an  un- 
broken condition. 


12  ARMOR-PIERCING   SHELLS 

General  Methods  of  Manufacture.  —  At  present,  there 
are  two  general  methods  of  manufacturing  high-explosive 
shells.  One  is  to  make  the  shell  from  bar  stock,  removing 
the  excess  material  to  form  the  cavity  by  means  of  high- 
power  drilling  machines ;  the  other  is  to  forge  the  shell  to 
approximately  the  correct  shape.  Until  within  the  last  few 
years,  cast-iron  shells  were  used  quite  extensively;  these 
were  cast  in  sand  molds  using  a  core  to  form  the  cavity. 
Great  difficulty,  however,  was  experienced  in  obtaining  a 
casting  free  from  flaws  and  other  imperfections,  so  this 
method  has  generally  been  superseded  by  either  the  forged 
or  bar-stock  shell.  When  the  shell  is  made  from  bar  stock, 
it  is  usually  necessary  to  fit  a  gas  plug  in  the  base  end  to 
eliminate  any  chances  of  piping.  At  present,  cast-iron 
shells  are  still  used  for  target  practice. 

High-explosive  shells  are  made  in  three  distinct  types. 
Those  with  a  solid  base  carrying  a  nose  fuse,  those  with  a 
solid  nose  carrying  a  base  fuse,  and  those  with  an  open  nose 
and  base  carrying  a  nose  fuse.  If  the  shell  is  intended  to 
carry  a  nose  fuse,  the  base  end  is  shaped  in  forging  by  the 
press  and  the  nose  subsequently  formed  to  shape  by  a  nos- 
ing-in  die.  In  small  shells  of  about  2  inches  in  diameter,  the 
nose  when  red-hot  can  be  spun  over  in  the  lathe  by  properly 
formed  tools.  However,  it  is  usually  closed  in  by  a  press. 
For  base  fuse  shells,  the  nose  is  produced  by  the  forging 
machine  and  the  base  is  subsequently  formed  by  pressing 
the  metal  to  the  required  shape. 

Operations  on  British  Forged  Shells. —  Generally  speak- 
ing, the  operations  on  a  British  high-explosive  shell  when 
made  from  f orgings  are  as  follows :  Bar  stock  of  the  re- 
quired diameter  is  first  cut  off  into  billet  lengths,  which  are 
heated  to  about  1900  degrees  F.  (about  1040  degrees  C.), 
and  by  subsequent  piercing  and  drawing  operations  are 
drawn  out  to  the  correct  length  and  diameter.  Following 
this,  the  mouth  end  and  base  end  are  trimmed  and  faced  off. 
Then  several  operations  are  performed  on  the  external  di- 
ameter of  the  shell,  such  as  turning,  grooving,  etc.  The  shell 
is  then  held  in  a  chuck  and  several  operations  are  performed 
on  the  cavity,  after  which  it  is  nosed-in ;  the  final  operations 


ARMOR-PIERCING  SHELLS  13 

consist  in  machining  the  nose,  pressing  on  the  band,  ma- 
chining it,  testing,  etc.  After  the  shell  has  been  completely 
machined,  it  is  filled  with  lyddite.  In  filling  the  shell,  great 
precautions  are  taken  to  prevent  the  melted  lyddite  (which 
contains  picric  acid)  from  coming  into  contact  with  certain 
materials,  such  as  combinations  of  lead  and  soda,  which  pro- 
duce sensitive  picrates.  The  shells  are  consequently  painted 
externally  with  a  special  non-lead  paint  and  lacquered  inter- 
nally with  a  special  lacquer.  The  picric  acid  is  then  melted 
in  a  pot,  the  temperature  being  carefully  controlled,  and 
certain  ingredients  are  added  to  reduce  the  melting  temper- 
ature of  the  acid.  The  melted  material  is  then  poured  into 
the  shell  through  a  bronze  funnel,  the  latter  forming  a  space 
for  the  exploder.  In  cooling,  the  material  solidifies  into  a 
dense  hard  mass. 

Operations  on  French  Forged  Shells.  —  The  French  high- 
explosive  shell  was  adopted  in  1886.  The  high-explosive 
used  in  this  shell  was  melenite,  which  was  originally  put 
into  an  ordinary  cast-iron  common  shell  having  thick  walls. 
Afterwards,  a  forged  steel  thin-walled  shell  was  introduced, 
as  shown  at  C,  Fig.  3 ;  this  is  hardened  and  heat-treated  in 
order  to  give  it  the  correct  tensile  strength.  The  operations 
on  the  French  shell  differ  from  those  on  the  British  shell 
in  that  no  machining  is  done  on  the  inside  of  the  shell  or  the 
cavity.  The  general  manufacturing  methods  on  this  shell 
are  first  cutting  off  a  billet  of  the  required  length,  heating, 
and  forging.  Usually  the  forgings  are  pickled;  then  the 
base  end  is  faced  and  centered,  the  external  diameter  is 
turned,  after  which  the  shell  is  nosed-in.  Following  the 
nosing-in  operation,  the  shell  is  hardened  and  tempered, 
after  which  it  is  faced  off  on  the  nose  end,  bored,  reamed, 
threaded,  and  finally  ground  or  turned  on  the  external  diam- 
eter ;  after  this  the  rifling  groove  is  cut  and  the  rifling  band 
pressed  in  and  turned  to  shape.  In  order  to  avoid  the  for- 
mation of  picrates,  the  interior  of  the  shell  is  lacquered  and 
the  external  surface  painted  with  a  non-acid  paint.  The 
melenite  is  then  melted  and  poured  in. 

High-explosive  Shell  Fuses. — Various  types  and  forms 
of  fuses  or  detonators  are  used  in  high-explosive  shells,  some 


14 


FUSES  AND  PRIMERS 


governments  using  a  plain  type  of  concussion  fuse  held  in 
the  base  end  of  the  shell,  and  to  which  no  gaine  is  attached ; 
this  fuse  is  set  off  upon  the  impact  of  the  shell  against  for- 
tifications or  other  obstructions.  Others  use  percussion 
fuses  of  extremely  complicated  design  which  are  provided 
with  exploders  that  extend  down  into  the  cavity  in  the  shell ; 
these  carry  a  detonating  primer  and  exploding  material  for 
detonating  the  high-explosive  contained  in  the  cavity  of  the 
shell.  Where  ordinary  black  powder  is  used  to  burst  the 
shell,  a  high-power  detonator  is  not  necessary.  The  direct- 
action,  or  impact,  fuses  are  more  simple  in  construction 


SAFETY  PLUG 


CONCUSSION  SPRING 
NEEDLE 

BOD 
EEDLE  AND  NEEDLE  DISK 


DETONATING 
COMPOSITION 


WRENCH  HOLES 


PRESSURE  PLATE 

Machinery 


Fig.  6.     Common  Types  of  Concussion  Fuses  used  in  Nose  and  Base  of 
High-explosive  Shells 

than  the  combination  time  and  percussion  fuses,  and  they 
are  usually  made  of  material  that  will  withstand  considera- 
ble pressure  without  crushing. 

High-explosive  shell  fuses  may  be  divided  into  two  dis- 
tinct groups :  Those  that  explode  instantaneously  upon  im- 
pact and  those  that  explode  shortly  after  impact,  or,  in  other 
words,  those  in  which  the  detonating  action  is  slightly  de- 
layed. From  the  standpoint  of  design  and  operation,  these 
groups  are  subject  to  still  further  divisions.  For  example, 
some  fuses  are  started  or  "unloaded"  by  the  gas  pressure 


FUSES  AND   PRIMERS 


15 


-— C 


Machinery 


in  the  gun,  others  depend  on  rotation,  and  some  depend  on 
a  combination  of  both ;  then  there  are  types  employing  split 
rings,  centrifugal  bolts,  springs,  etc.,  or  a  combination  of 
two  or  more  actions. 

Common  Type  of  Concussion  Fuse.  —  A  common  type  of 
concussion,  or  direct-action,  fuse  that  fits  in  the  nose  of 
the  shell  and  is  set  off  upon  impact  is  shown  at  A,  Fig.  6. 
The  fuse  body  and  other  important  members  are  made  from 
steel  of  sufficient  strength  to  be  discharged  from  the  gun 
without  rupture;  but,  upon  striking,  the  needle  disk  is 
crushed  in  and  the  needle  explodes  the  detonator,  which,  in 

turn,      explodes      the 

powder  in  the  base  of 
the  fuse.  At  B  is 
shown  the  common 
type  of  concussion  fuse 
used  in  the  base  of 
high-explosive  shells. 
Before  firing,  the 

needle     pellet     is     held          Fig.  7.     Base  Fuse  used  in  American  Small- 

by  a  central  spindle  and  Medium-callber  nigh-expiosive  shells 
that  has  a  pressure  plate  attached  to  its  rear  end.  A  cen- 
trifugal bolt  is  also  inserted  for  additional  safety,  which  is 
released  by  the  rotation  of  the  shell.  In  action,  this  fuse 
works  as  follows :  On  the  discharge  of  the  projectile  from 
the  gun,  the  gas  pressure  pushes  in  the  pressure  plate  so 
that  the  central  spindle  is  carried  forward,  unlocking  the 
centrifugal  bolt.  The  needle  pellet  is  then  free  to  move 
forward  and  explode  the  detonating  cap  when  the  shell 
strikes.  These  two  types  of  fuses  are  not  very  extensively 
used  at  the  present  time,  and  have  been  superseded,  in  gen- 
eral, by  more  complicated  but  effective  fuses. 

American  Base  Percussion  Fuse. —  In  American  high-ex- 
plosive shells  fired  from  one-  and  two-pounders,  as  well  as 
from  six-pounders  and  2.38-inch  field  guns,  the  type  of  fuse 
shown  in  Fig.  7  is  used.  This  fuse  is  of  simple  construction 
and  depends  for  its  action  on  the  expanding  of  a  split  ring  A. 
As  the  primer  end  of  the  fuse  is  toward  the  interior  of  the 
shell,  the  flame  passes  from  the  priming  charge  B  directly 


16 


FUSES   AND   PRIMERS 


to  the  bursting  charge  in  the  shell  without  passing  through 
the  body  of  the  fuse  itself.  The  primer  cup  contains  the 
percussion  composition  and  priming  charge,  and  is  enclosed 
at  its  outer  end  by  a  brass  disk  C  secured  in  place  by  crimp- 
ing over  the  outer  end  of  the  primer  holder,  or  brass  closing 
screw  D.  The  act  of  arming  this  fuse  is  simple,  and  de- 
pends on  the  expanding  of  the  split  ring,  which  is  accom- 
plished when  the  shell  strikes  a  solid  body. 

Centrifugal  Type  of  Base  Percussion  Fuse.  —  In  the 
case  of  ring-resistance  fuses,  or,  in  fact,  in  any  fuse  the 
action  of  which  depends  on  the  longitudinal  stresses  de- 
veloped by  the  pressure  in  the  gun,  the  conditions  of  safety 
in  handling  and  certainty  of  action  are  not  all  that  could 


GUN  COTTON 


DETONATING  COMPOSITION 


Machinery 


Fig.  8.     Frankford   Arsenal   Centrifugal   Type  of   Base   Per- 
cussion  Fuse 

be  desired.  A  fuse  that  is  armed  by  the  centrifugal  force 
developed  by  the  rotation  of  the  projectile,  and  which  is 
safe  until  the  maximum  velocity  of  rotation  is  nearly  ob- 
tained, is  the  Frankford  arsenal  fuse  shown  in  Fig.  8,  where 
a  separate  view  of  the  expanding  centrifugal  plunger  pre- 
sents the  firing  pin  in  the  armed  position. 

This  fuse  is  used  in  shells  fired  from  mountain  guns, 
howitzers,  and  mortars.  It  is  made  up  of  the  body  A  and 
the  closing  screw  B,  which  are  held  in  the  steel  stock  C; 
this  stock  also  carries  the  detonating  charge.  The  primer 
or  detonating  agent  is  also  held  in  the  nose  of  the  fuse,  and, 
to  reach  the  exploder,  the  flame  passes  through  a  small  vent 
in  the  primer  closing  screw  D  to  the  guncotton,  which  f  acil- 


FUSES  AND   PRIMERS  17 

itates  and  increases  the  igniting  effect.  The  centrifugal 
plunger,  shown  in  the  armed  position  at  H,  is  made  in  two 
parts.  When  the  fuse  is  at  rest,  these  are  held  together 
by  the  pressure  of  a  spiral  spring  F  contained  in  the  cylin- 
drical bushing  G  secured  to  each  end  of  the  plunger  halves. 
The  spring  exerts  its  pressure  on  half  of  the  plunger 
through  the  bolt  7.  Pivoted  in  a  recess  in  one  half  of  the 
plunger  is  the  firing  pin  J,  which,  when  the  fuse  it  at  rest, 
is  held  with  its  point  below  the  front  surface  of  the  plunger 
by  the  lever  action  of  the  link  K  that  is  pivoted  to  the 
other  half.  When  subjected  to  the  action  of  centrifugal 
force  developed  by  the  rapid  rotation  of  the  projectile  in 
passing  from  the  bore  of  the  gun,  the  two  halves  of  the 
plunger  separate.  This  separating  movement  causes  the 
rotation  of  the  firing  pin  /,  the  point  of  which  is  now  held 
in  advance  of  the  front  surface  of  the  plunger,  to  pierce 
the  brass  primer  shield  and  ignite  the  detonating  composi- 
tion. When  the  fuse  is  armed,  the  end  of  the  link  K  rests  on 
the  pivot  of  the  firing  pin,  thus  affording  support  to  the 
firing  pin  when  it  strikes  the  percussion  primer.  The 
amount  of  separation  of  the  plunger  parts  is  limited  by 
the  nut  M  coming  to  a  bearing  on  a  shoulder  in  the  bush- 
ing G,  and  thus  preventing  the  diameter  of  the  expanding 
plunger  from  equalling  the  full  diameter  of  the  hole  in  the 
fuse  body.  A  stud  screwed  into  the  head  of  the  fuse  stock 
engages  a  corresponding  slot  cut  through  the  bottom  of 
both  plunger  halves  and  insures  the  rotation  of  the  plunger 
with  the  shell.  The  strength  of  the  spring  F  is  adjusted 
so  that  the  fuse  will  not  arm  until  its  rapidity  of  rotation 
is  a  certain  percentage  of  that  exerted  in  the  shell  in  which 
it  is  used,  and  so  that  it  will  surely  arm  whenever  the 
rapidity  of  revolution  approximates  the  speed  of  rotation 
of  the  shell  when  fired.  In  the  case  of  the  parts  of  the 
plunger  being  accidentally  separated  and  the  fuse  armed 
by  a  sudden  jolt  or  jar  in  transportation  or  handling,  the 
reaction  of  this  spring  will  immediately  bring  the  plunger 
back  to  its  unarmed  position. 

British  High-explosive  Fuse. —  The  fuse  shown  in  Fig.  9 
is  known  as  the  British  100-graze  high-explosive  fuse,  and 


18 


FUSES  AND   PRIMERS 


is  used  in  British  high-explosive  shells  that  are  fired  from 
field  and  mountain  guns.  This  fuse  explodes  upon  impact 
only  and  screws  into  the  nose  of  the  shell;  all  the  parts, 
except  the  adapter  and  gaine,  are  made  from  brass  or 
bronze.  This  fuse  operates  as  follows :  When  the  shell  is 


Machinery 


Fig.  9.     British   No.  100  Graze   High-explosive  Shell   Fuse 

fired,  and  before  it  commences  its  rotary  motion  imparted 
by  the  rifling  in  the  gun  bore,  the  impact  of  the  explosive 
charge  in  the  case  causes  the  combined  top  and  bottom  de- 
tent A  and  B,  respectively,  to  drop  back  and  compress  the 
detent  spring  C.  The  detent  assembly  is  made  in  two 


FUSES  AND   PRIMERS  19 

pieces ;  and,  as  the  stem  A  is  free  to  move  out  of  alignment, 
it  drops  to  one  side,  by  the  action  of  gravity,  when  it  is 
forced  back.  It  is  caught  by  the  edge  of  the  counterbored 
hole  and  prevented  from  taking  its  original  position.  By 
this  time,  the  centrifugal  action  of  the  shell  throws  centri- 
fugal bolt  D,  the  path  of  which  is  now  clear,  out  of  the  way 
of  the  graze  pellet  E.  The  only  member  that  now  prevents 
detonation  is  the  hair  spring  F,  so  the  slightest  impact 
causes  the  relatively  heavy  graze  pellet  to  jump  forward 
and  explode  the  shell.  The  primer  that  is  held  in  the  coun- 
terbored end  of  the  graze  pellet  is  exploded  upon  impact 
with  needle  G,  and  from  here  the  flame  extends  down  into 
the  other  explosives  in  the  gaine.  The  primer  in  pellet  E 
is  loaded  with  a  composition  composed  of  45  parts  chlorate 
of  potassium,  23  parts  sulphide  of  antimony,  and  32  parts 
fulminate  of  mercury.  The  different  constituents  are  meas- 
ured by  weight,  and  are  loaded  into  the  primer  cup  under 
a  pressure  of  600  pounds,  after  which  the  cup  carrying  the 
explosive  charge  is  dried. 

Should  the  primer  in  the  pellet  E,  for  any  reason,  fail  to 
explode,  a  second  detonation  takes  place  simultaneously. 
As  shown  by  the  view  to  the  right,  the  lower  end  of  pellet 
E  is  tapered  and  seated  in  a  cross-hole  in  the  percussion 
pellet  H.  When  the  graze  pellet  moves  forward,  pellet  H 
is  released  and  the  centrifugal  action  combined  with  spring 
I  drives  the  pellet  carrying  needle  /  against  primer  K,  ex- 
ploding it.  The  flame  passes  through  four  small  holes  in 
the  needle  holder  L,  thence  into  the  chamber  and  down  into 
the  gaine  containing  the  detonating  charges. 

The  gaine  is  held  to  the  fuse  body  by  adapter  M.  Its 
three  chambers,  N,  0,  and  P,  contain  different  high-explo- 
sives, each  succeeding  one  being  of  greater  power  than  the 
last.  Chamber  P  is  filled  with  lyddite  in  flake  form.  The 
flame  from  the  detonating  primers  first  explodes  the  ma- 
terial in  chamber  N,  then  that  in  chamber  0,  and  then  that 
in  chamber  P,  which  causes  such  a  terrific  shattering  effect 
that  the  lyddite  in  the  shell  is  detonated  and  blows  the  shell 
to  atoms — some  parts  to  the  fineness  of  sand.  It  is  stated 
upon  good  authority  that,  after  a  shell  has  been  detonated, 


20 


FUSES  AND  PRIMERS 


it  is  impossible  to  find  the  gaine  or  its  parts,  so  terrific  is 
the  effect  of  the  explosion. 

Russian  High-explosive  Fuse.  —  The  Russian  high-explo- 
sive fuse  or  detonating  head  used  in  high-explosive  shells 
is  shown  in  Fig.  10 ;  the  gaine  is  a  part  of  the  head  and  ex- 
tends into  the  explosive  material  in  the  cavity  of  the  shell. 


Machinery 


Fig.  10.     Russian  High-explosive  Shell   Detonating  Head 

This  fuse  operates  in  the  following  manner :  The  force  of 
impact  of  the  shell  against  a  solid  body  overcomes  the  re- 
sistance of  spring  A  and  stirrup  B,  allowing  striker  rod  C 
to  move  forward  into  the  cavity  occupied  by  spring  A. 
Attached  to  the  lower  end  of  striker  rod  C  is  a  detonator 
pellet  D,  which  carries  a  charge  of  mercury  fulminate,  and, 
in  coming  in  contact  with  the  steel  needle  E,  is  exploded. 


MELENITE  POWDER 


tVTT 


Machinery 


Fig.  11.     French  Detonating  Fuse  for  Use  in  75-millimeter 
High-explosive  Shells 

When  exploded,  pellet  D  is  midway  along  the  interior  of  the 
"tetryl"  cartridge  /  that  surrounds  the  striker  rod  C,  so 
that  the  latter  is  detonated*  and,  in  turn,  explodes  the  high- 
explosive  material  held  in  the  cavity  of  the  shell.  Needle  E 
is  held  in  a  steel  plug  F,  which  is  kept  from  moving  up  with 
the  striker  rod  C  by  a  striker  casing  G  crimped  around  it, 


FUSES   AND   PRIMERS  21 

and  extending  up  through  the  body  of  the  fuse,  coming  in 
contact  with  the  lower  face  of  the  head  plug  H.  In  order 
that  the  body  of  this  detonator  will  be  capable  of  resisting 
considerable  shock,  it  is  generally  made  from  alloy  steel 
with  a  tensile  strength  of  about  110,000  pounds  per  square 
inch. 

French  High-explosive  Fuse.  —  A  high-explosive  shell 
fuse  of  the  delay-action  type  used  in  the  French  75-milli- 
meter high-explosive  shell  is  shown  in  Fig.  11.  This  is 
provided  with  a  safety  head  and  is  carried  in  the  nose  of 
the  shell.  In  action,  this  fuse  works  as  follows:  On  the 
discharge  of  the  projectile  from  the  bore  of  the  gun,  the 
gas  pressure  overcomes  the  resistance  of  spring  A,  causing 
bushing  B  to  drop  back ;  the  stirrup  C,  which  is  held  to  it, 
then  grips  the  head  of  the  plunger  D.  The  plunger  D  com- 
pletely envelopes  the  firing  pin  E  and  prevents  the  detona- 
tor F  from  being  accidentally  discharged.  When  this 
plunger  is  withdrawn,  it  exposes  the  firing  pin  E,  which 
is  riveted  to  the  retainer  G,  and  does  not  move  with  the 
plunger. 

The  fuse  is  now  in  the  armed  position,  so,  as  soon  as  the 
projectile  strikes  a  solid  body,  the  resistance  of  springs  / 
and  J  is  overcome  and  the  primer  F  makes  contact  with 
the  firing  pin  E.  The  flame  from  the  primer  F  ignites  the 
guncotton  K  and  the  powder  surrounding  it ;  this  ignites  the 
compressed  gunpowder  in  cups  L  and  M,  which  results  in 
quite  a  powerful  explosion  and  explodes  the  detonating  com- 
position in  cup  N;  this,  in  turn,  explodes  the  detonator  0, 
which  is  filled  with  melenite  in  flake  form.  The  fuse  does 
not  detonate  the  high-explosive  composition  in  the  shell  in- 
stantaneously, but  causes  a  series  of  explosions,  finally  re- 
sulting in  the  detonation  of  the  melenite  in  the  shell  by  the 
exploder  that  extends  into  it.  All  the  working  parts  of 
this  fuse  are  made  from  brass  or  bronze  with  the  exception 
of  the  safety  cap  P,  nose  Q,  cup  R,  and  exploder  cup  S; 
these  are  made  of  steel. 

Loading  Propelling  Charges  in  Guns  and  Howitzers.  — 
In  the  early  cannon,  the  spherical  shot  and  powder  charges 
were  rammed  in  from  the  muzzle  of  the  gun  the  same  as  in 
loading  small  arms.  It  was  not  until  1845  that  a  success- 


22 


FUSES  AND  PRIMERS  23 

• 

ful  breech-loading  gun  was  designed ;  in  this  case,  the  pro- 
jectile, which  bore  a  marked  resemblance  to  the  present-day 
type,  was  placed  in  the  gun  from  the  breech  end  with  a  pro- 
pelling charge  of  black  powder  packed  in  behind  it,  the  vent 
being  closed  by  a  hinged  door.  Following  this,  several 
types  of  breech-closing  mechanism  were  developed,  and,  in 
England  in  1854,  the  Armstrong  breech-loading  gun  was  de- 
signed. The  projectile  and  propelling  charge,  however, 
were  still  made  up  in  separate  units,  and  it  was  not  until 
some  time  later  that  fixed  ammunition  was  used  in  field 
guns.  In  early  cannon,  the  barrels  were  made  from  either 
bronze  or  cast  iron,  bronze  being  used  for  field  guns  and 
cast  iron  for  large  coast  artillery.  These  two  metals  were 
subsequently  abandoned,  forged  steel  being  used  in  their 
place. 

Fixed  Ammunition.  —  Fixed  ammunition  is  the  name 
given  to  that  class  of  shells  in  which  the  propelling  charge 
for  the  projectile  is  held  in  a  cartridge  case  attached  to  the 
rear  end  of  the  projectile.  In  other  words,  the  projectile, 
propelling  charge,  and  firing  member  or  primer  form  a  com- 
plete unit.  The  diagram  at  A,  Fig.  12,  shows  a  sectional 
view  of  a  3-inch  field  gun  with  the  complete  round  of  am- 
munition inserted  in  the  breech.  It  will  be  noticed  that  the 
gun  is  chambered  to  receive  the  projectile  and  cartridge 
case,  and  carries  a  breech-block  containing  the  striker 
mechanism.  Upon  the  operation  of  the  striker  mechanism, 
firing  pin  a  hits  primer  6,  igniting  the  percussion  cap  in  its 
head,  which,  in  turn,  ignites  the  black-powder  charge  in  the 
body  of  the  primer  itself.  The  propellant  in  the  cartridge 
case  c  is  now  ignited  and  almost  instantly  converted  into 
a  gas.  The  gas  thus  formed  occupies  a  much  greater  vol- 
ume than  the  original  material,  with  the  result  that  the 
projectile  e  is  started  on  its  journey  through  the  bore  of  the 
gun. 

As  soon  as  the  projectile  starts  forward,  the  copper 
rifling  band  d  is  forced  into  the  rifling  grooves  in  the  bore 
of  the  gun,  which  are  located  in  a  helical  path.  This  results 
in  the  projectile  being  rotated  at  the  same  time  that  it  ad- 
vances. In  addition,  the  rifling  band  also  centers  the  pro- 


24  FUSES  AND   PRIMERS 

jectile  and  prevents  the  propelling  gas  from  escaping  past 
it.  Modern  propellants,  by  virtue  of  their  ingredients,  are 
of  the  slow-burning  variety ;  consequently,  the  gas  pressure 
increases,  with  the  result  that  the  projectile  increases  in 
velocity  from  the  time  that  it  leaves  the  breech  until  it 
reaches  the  muzzle  of  the  gun.  To  provide  for  this,  the 
rifling  grooves  in  some  guns  increase  in  pitch  as  they  reach 
the  muzzle  of  the  gun.  For  example,  in  the  3-inch,  Ameri- 
can, quick-firing  field  gun,  the  rifling  grooves  start  at  the 
breech  with  a  twist  of  one  turn  in  50  calibers  and  increase 
to  one  turn  in  25  calibers  at  a  distance  of  2i/2  calibers  from 
the  muzzle.  Therefore,  as  the  velocity  of  the  projectile  is 
increased,  the  speed  of  rotation  upon  its  axis  is  accelerated ; 
this  partly  accounts  for  the  comparatively  flat  trajectory 
of  the  modern  high-power  quick-firing  gun  in  comparison 
with  the  older  and  less  efficient  guns. 

Loading  Howitzers  and  Mortars.  — A  howitzer  differs 
from  a  quick-firing  field  gun  in  several  ways :  The  barrel 
is  much  shorter;  no  cartridge  case  is  used  (except  for  me- 
dium-caliber howitzers,  where  a  short  case  is  sometimes 
used)  ;  the  muzzle  velocity  is  only  about  one-half  that  of  a 
quick-firing  gun  of  the  same  caliber ;  and  a  howitzer  is  used 
for  high-angle  firing,  particularly  against  troops  protected 
by  entrenchments  or  other  shelter.  The  diagram  B,  Fig.  12, 
shows  a  section  through  the  barrel  of  a  4.5-inch  howitzer. 
The  projectile  /  is  not  fixed  to  the  cartridge  case  g;  in  fact, 
it  is  separated  from  it.  The  difference  between  this  cart- 
ridge case  and  the  one  shown  at  A  is  in  length  only;  the 
length  of  this  cartridge  case  is  about  one-half  the  caliber. 
The  howitzer  cartridge  case  carries  a  comparatively  light 
propelling  charge  of  smokeless  powder  h,  which  is  held  in 
the  case  by  wads.  Having  the  ammunition  arranged  in  this 
manner  makes  it  possible  to  vary  the  charge  according  to 
the  results  wanted.  In  larger-bore  howitzers,  6-inch  caliber, 
a  charge  of  powder  in  the  form  of  doughnuts  or  large  disks 
is  used ;  these  are  placed  directly  in  the  breech  of  the  gun, 
and  no  cartridge  case  is  used. 

A  type  of  gun  that  bears  a  marked  resemblance  to  the 
howitzer  is  the  mortar,  which  is  classified  as  field  or 


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26 


FUSES  AND  PRIMERS 


pelling  charges  are  separated.  Fig.  13  shows  a  sec- 
tion taken  through  the  chamber  and  barrel  of  a  6-inch 
rapid-fire  gun.  Here,  the  projectile  i  is  separate;  and 
located  between  the  projectile  and  the  breech-block  is 
a  propelling  charge  of  smokeless  powder  and  detonating  cap 
contained  in  silk  bags  ;,  the  number  of  bags  depending  on 
the  size  of  the  gun  and  the  weight  of  the  charge  put  up  in 
each.  These  bags  are  made  from  raw  silk  with  the  ends 
made  double-ply,  and  between  the  two  pieces  at  each  end 


BLACK  POWDER 


Machinery 


Fig.  14.     Friction,  Electric  and  Percussion  Primers 

is  placed  a  priming  charge  of  black  powder  quilted  in,  in 
squares  of  about  2  inches,  and  uniformly  spread  over  the 
surface.  The  charge  used  for  propelling  a  projectile  of  this 
particular  size  of  gun  weighs  about  24  pounds ;  consequently, 
only  two  bags  would  be  needed.  The  obturator  h  acts  as 
a  gas  check  and  at  its  rear  end  carries  the  electric  primer. 
The  powder  charge  is  ignited  by  means  of  a  friction  or  elec- 
tric primer  shown  at  A,  B,  and  C,  Fig.  14.  The  primer,  of 
course,  is  not  a  part  of  the  propelling  charge,  but  is  held 
in  the  breech-block  of  the  gun.  In  larger-bore  guns,  several 
bags  of  smokeless  powder  are  inserted ;  for  instance,  in  the 


FUSES  AND  PRIMERS  27 

16-inch  American  gun,  six  bags  containing  a  total  of  666.5 
pounds  of  smokeless  powder  are  used. 

Friction,  Electric,  and  Percussion  Primers.  —  Various 
types  of  primers  are  used  in  howitzers  and  field  guns  for 
igniting  the  propelling  charges.  For  guns  using  fixed  am- 
munition, the  primer  is  carried  in  the  base  of  the  cartridge 
case;  whereas,  for  guns  firing  loose  projectiles,  the  primer 
is  held  in  the  breech-block.  Inasmuch  as  large-  and  me- 
dium-size caliber  projectiles  are  discussed  here,  two  of  the 
principal  types  of  primers  used  in  the  breech-blocks  are 
described. 

Friction  Primers.  —  Fig.  14  shows  the  common  type  of 
friction  primer,  which  may  be  fired  by  friction  or  electric- 
ity. As  the  f  rictional  and  electrical  elements  are  independ- 
ent, this  primer  may  be  fired  by  friction  should  it  fail  to  fire 
by  electricity.  This  primer  comprises  a  brass  case  a  held 
in  the  breech-block  of  the  gun,  and  carrying  a  case  b  en- 
closing the  firing  or  igniting  elements.  When  used  as  a 
friction  primer,  an  annular  pellet  c  of  friction  composition 
is  pressed  into  the  inner  case  b  and  rests  on  a  vulcanite 
washer  d,  which  prevents  it  from  crumbling  when  the  firing 
rod  e  is  pulled  to  ignite  the  primer.  The  inner  end  of  the 
firing  rod  e  is  loosely  surrounded  by  a  serrated  cylinder  g, 
which  is  embedded  up  to  the  serrations  in  the  friction  com- 
position. The  inner  end  of  the  firing  rod  is  provided  with 
a  head  that  operates  upon  the  cylinder  g,  and  these  parts 
are  securely  held  in  place  by  forked  lever  h  and  nut  i;  this 
end  is  shown  enlarged  at  B. 

In  operation,  when  the  firing  rod  e  is  pulled,  the  serrated 
cylinder  g  is  drawn  through  the  composition  c  and  ignites 
it.  As  the  conical  end  of  the  cylinder  is  then  drawn  to  its 
seat  in  the  rear  part  of  the  primer,  it  prevents  the  escape 
of  gas  at  the  rear.  The  flame  from  the  friction  composition 
passes  through  vents  in  the  closing  nut  i  and  ignites  the 
priming  charge  of  compressed  and  loose  black  powder  in  the 
body  of  the  primer.  The  resulting  explosion  blows  out  the 
cemented  brass  cup  j  in  the  mouth  of  the  primer  and  allows 
the  flame  to  pass  through  the  breech-block  to  the  propelling 
charge  in  the  breech  of  the  gun. 


28  FUSES  AND  PRIMERS 

Electric  Primers. —  In  order  to  adapt  this  primer  for 
electric  firing,  the  rod  e  is  covered  with  an  insulating  cylin- 
der k  and  enters  the  primer  through  a  vulcanite  plug  I.  The 
rod  e  is  in  electric  contact  with  the  serrated  cylinder  g,  but 
this  is  insulated  from  the  primer  body  by  a  washer  d  and  the 
pellet  of  friction  composition,  which  is  a  non-conductor  of 
electricity.  The  electric  circuit  is  completed  by  a  platinum 
wire  m  soldered  to  the  fork  h  and  nut  i  and  surrounded  by 
an  igniting  charge  of  guncotton. 

In  operation,  when  the  primer  is  inserted  in  the  gun,  the 
insulated  button  n  on  the  rod  e  is  grasped  by  an  electric 
contact  piece  through  which  the  electric  current  passes.  The 
passage  of  the  electric  current  then  heats  the  platinum  wire, 
igniting  the  guncotton  and  the  priming  charge  of  powder. 

Percussion  Primers.  —  In  fixed  ammunition  where  the 
cartridge  case  forms  a  unit  with  the  projectile,  the  firing 
is  done  by  means  of  a  primer  held  in  the  cartridge  case ;  D, 
Fig.  14,  shows  the  primer  used  in  the  head  of  American 
3-inch  cartridge  cases.  This  is  known  as  the  110-grain  per- 
cussion primer,  and  consists  of  a  brass  case  o  resembling 
in  shape  a  small-arms  cartridge  case,  in  which  a  percussion 
cap  is  held.  The  head  or  rear  end  of  the  primer  case  is  coun- 
tersunk to  form  a  cup-shaped  recess  in  which  the  percussion 
primer  proper  d  is  located.  The  latter  consists  of  a  cup, 
anvil,  and  percussion  composition,  which  is  composed  of 
the  following  ingredients: 

Ingredients  Per  Cent 

Chlorate  of  Potash 49.6 

Sulphide  of  Antimony 25.1 

Glass   (ground)    16.6 

Sulphur   8.7 

Owing  to  the  danger  involved  in  the  handling  of  mixtures 
containing  fulminate  of  mercury,  the  Frankford  arsenal 
has  abandoned  this  ingredient  and  substituted  the  ingre- 
dients just  given  for  the  service  primers. 

The  percussion  cap  recess  is  connected  with  the  interior 
of  the  primer  case  by  two  small  vents.  The  body  of  the  case 
contains  110  grains  of  black  powder  that  constitutes  the 
rear  "priming"  or  igniting  charge  for  the  smokeless-powder 


FUSES  AND  PRIMERS 


29 


propellant.  This  black  powder  is  inserted  in  the  case  under 
a  pressure  of  36,000  pounds  per  square  inch,  and  is  pressed 
into  the  primer  body  around  a  central  wire  which  is  then 
withdrawn,  leaving  a  longitudinal  hole  the  full  length  of  the 
powder  charge.  Eight  radial  holes  are  then  drilled  through 
the  primer  body  and  compressed  powder,  thus  affording  six- 
teen vents  for  the  free  exit  of  the  black-powder  flames  to 
the  smokeless-powder  charge.  After  filling  the  case,  the 
front  end  is  closed  by  a  cardboard  wad  covered  with  shellac 
and  the  radial  perforations  are  covered  by  a  tin-foil  wrap- 
per so  as  to  retain  any  loose  black  powder  and  exclude 
moisture. 

In  action,  the  firing  pin  hits  the  percussion  cap  and  ex- 
plodes it.     This  ignites  the  black-powder  charge,  and  the 


Machinery 


Fig.  15.     Percussion  Primer  used  in  British  Cartridge  Cases 

flames  from  the  latter  shoot  out  through  the  vents  in  the 
case  and  ignite  the  smokeless-powder  charge.  In  order  to 
make  the  combustion  of  the  smokeless  powder  complete,  a 
second  igniting  or  priming  charge  is  generally  used.  In  the 
3-inch  shell,  this  additional  charge  consists  of  14  ounce  of 
black  powder  which  is  contained  in  a  disk-shaped  bag  placed 
in  the  case  directly  in  front  of  the  smokeless-powder  charge. 
British  Percussion  Primer.  —  A  percussion  primer  that 
differs  considerably  from  that  illustrated  at  D,  Fig.  14,  is 
shown  in  Fig.  15;  this  primer  is  used  in  British  18-pound 
cartridge  cases.  It  comprises  a  brass  cup  A  threaded  on  the 
external  diameter  so  as  to  screw  into  the  pocket  in  the  head 


30  FUSES  AND  PRIMERS 

of  the  case,  and  recessed  and  threaded  to  receive  the  anvil 
B.  This,  in  turn,  is  counterbored  to  receive  a  brass  ball  C 
and  is  also  provided  with  three  fire  holes.  It  is  backed  by 
a  plug  D  that  is  sealed  with  a  paper  disk  E  secured  with 
Pettman's  cement.  Seated  on  the  head  of  anvil  B  is  the 
percussion  composition,  which  is  pressed  into  the  soft  brass 
cup  F,  and  inside  of  which  is  a  tin-foil  washer.  The  percus- 
sion composition,  known  as  the  1.2-grain  composition,  con- 
sists of  the  following  ingredients : 

Ingredients  Per  Cent 

Sulphide  of  Antimony 54.5 

Chlorate  of  Potash 36.5 

Glass  (ground)    3.0 

Powder  (mealed)    3.0 

Sulphur   3.0 

In  the  front  end  of  the  primer  enclosed  by  a  brass  closing 
disk  G  is  a  charge  of  RFG2  powder.  Separating  the  closing 
disk  and  the  powder  is  a  paper  disk  H  secured  with  Pett- 
man's cement.  The  closing  disk  G  is  held  in  place  by  spin- 
ning over  the  front  edge  of  the  cup  A. 

In  action,  the  firing  pin  comes  directly  in  contact  with  the 
percussion  cap  F,  exploding  it  and  causing  the  flames  to 
pass  through  the  vents  in  the  anvil  B  and  the  plug  D.  The 
paper  disk  E  is  thus  ignited,  together  with  the  powder 
charge  in  the  front  end  of  the  primer.  The  resulting  pres- 
sure forces  out  the  center  of  the  closing  disk  G,  which  is 
weakened  by  six  radial  slots.  The  flame  then  passes  to  the 
secondary  powder  charge  in  the  base  of  the  cartridge  case, 
thus  effecting  complete  combustion  of  the  propelling  charge. 
In  order  to  prevent  the  escape  of  gas  back  through  the  vents 
in  the  primer  before  complete  combustion  has  taken  place,  a 
soft  brass  ball  C  is  inserted  in  the  anvil.  As  soon  as  the 
powder  in  the  front  of  the  primer  is  ignited,  the  resultant 
back  pressure  forces  the  ball  into  the  circular  seat  in  the 
anvil  and  effectively  prevents  the  further  escape  of  gas. 

Combination  Electric  and  Percussion  Primer.  —  The 
United  States  Navy  uses,  in  rapid-fire  guns,  a  combination 
electric  and  percussion  primer  of  the  type  shown  at  C,  Fig. 
14.  When  fired  by  percussion,  the  percussion  cap  r  is  not 


FUSES  AND  PRIMERS  31 

struck  directly  by  the  firing  pin,  but  the  point  of  the  pin 
forces  in  the  head  of  the  cup  t  and  this,  in  turn,  advances 
plug  s.  The  electric  ignition  is  effected  through  the  brass 
cup  t  to  which  one  end  of  the  platinum  wire  u  is  soldered. 
A  small  quantity  of  guncotton  surrounds  this  wire.  Electric 
contact  is  made  with  cup  t  by  the  insulated  firing  pin  of  the 
gun.  This  cup  is  insulated  from  the  body  of  the  primer 
by  the  cylinder  iv  and  bushing  v,  both  of  which  are  made  of 
vulcanite.  The  brass  contact  bushing  y  to  which  the  other 
end  of  the  platinum  wire  is  soldered  completes  the  electrical 
connection. 


CHAPTER  II 
EXPLOSIVES,  DETONATORS  AND  FULMINATES 

REFERENCE  to  Fig.  3  will  show  that  a  high-explosive  shell 
of  the  fixed-ammunition  type  comprises  four  principal  parts ; 
namely,  the  projectile,  fuse  (detonating),  cartridge  case, 
and  primer.  The  projectile  carries  the  high-explosive  that, 
when  detonated,  produces  such  a  powerful  shattering  effect 
that  the  steel  shell  is  blown  into  atoms.  The  high-explosive 
in  the  shell  is  detonated  by  other  very  powerful  explosives 
contained  in  the  gaine  of  the  detonating  fuse.  In  the  fuse 
proper,  as  many  as  four  classes  of  explosives  are  used; 
namely,  fulminate  of  mercury,  black  powder,  picric  acid, 
and  compounds  of  a  similar  nature  so  combined  as  to  make 
their  explosive  effect  of  different  strengths.  The  cartridge 
case  carries  a  propellant,  usually  nitrocellulose  or  nitrogly- 
cerine, that  is  put  up  in  the  form  of  flakes,  long  tubes,  per- 
forated grains,  or  flat  strips.  It  also  contains  one  or  two 
charges  of  common  black  powder.  One  charge  is  located 
between  the  smokeless  powder  and  the  projectile;  the  other 
is  located  next  to  the  primer  pocket  and  assists  the  priming 
charge  in  effecting  complete  combustion  of  the  propelling 
charge.  The  primer  usually  contains  two  explosive  agents ; 
namely,  fulminates  or  chlorates,  and  black  powder. 

Classification  of  Explosives.  —  The  explosives  used  in 
high-explosive  shells,  cartridge  cases,  fuses,  and  primers, 
may  be  divided  into  three  general  classes:  Progressing  or 
propelling  explosives,  known  as  "low  explosives";  detonat- 
ing or  disruptive  explosives,  known  as  "high-explosives"; 
and  detonators,  known  as  "fulminates"  or  "chlorates."  The 
first  of  these  includes  black  gunpowder,  smokeless  powder, 
and  black  blasting  powder;  the  second,  dynamite,  nitro- 
glycerine, guncotton,  etc.;  the  third,  fulminates  and  chlor- 

32 


EXPLOSIVES  AND  DETONATORS  33 

ates.  In  all  classes  of  explosives,  the  effect  of  the  explosion 
is  dependent  on  the  quantity  of  gas  and  heat  developed  per 
unit  of  weight,  the  volume  of  the  explosion,  the  rapidity  of 
reaction,  and  the  character  of  the  confinement,  if  any,  in 
which  the  explosive  charge  is  placed. 

Black  Gunpowder.  —  The  most  common  of  all  explosives 
is  black  gunpowder.  The  earliest  known  use  of  gunpowder 
was  in  the  sixteenth  century,  at  which  time  it  was  used  in  the 
form  of  fine  powder  or  dust.  No  marked  improvement  was 
made  in  this  explosive  until  1860,  when  General  Rodman, 
of  the  Ordnance  Department  of  the  United  States  Army, 
discovered  the  principle  of  progressive  combustion ;  this  con- 
sisted in  using  larger  grains  of  greater  density  so  that  the 
rate  of  combustion  could  be  more  uniformly  controlled.  The 
increased  density  diminished  the  rate  of  combustion,  so  that 
black  powder  in  this  form  developed  less  gas  in  the  first 
instant  of  combustion  and  the  volume  of  gas  increased  as 
the  projectile  moved  through  the  bore  of  the  gun.  Black 
gunpowder  is  usually  made  up  of  a  mechanical  mixture  of 
niter,  charcoal,  and  sulphur  in  the  proportions  of  70  parts 
niter,  15  charcoal,  and  10  sulphur.  The  niter  furnishes  the 
oxygen  to  burn  the  charcoal  and  sulphur,  the  charcoal  fur- 
nishes the  carbon,  and  the  sulphur  gives  density  of  grain  to 
the  powder  and  lowers  its  point  of  ignition. 

The  manufacture  of  black  gunpowder  is  comparatively 
simple.  The  ingredients  are  ground  and  pulverized,  after 
which  the  correct  proportions  of  each  ingredient  are  inti- 
mately mixed  in  an  incorporating  mill  consisting  of  two 
heavy  iron  wheels  mounted  to  run  in  a  circular  bed;  the 
product  is  called  a  "mill  cake."  The  mill  cake  is  then  sub- 
jected to  pressure  in  a  hydraulic  press  and  forms  what  is 
known  as  a  "press-cake."  The  cake  from  the  press  is 
broken  up  into  grains  by  passing  through  rollers  and  the 
grains  are  graded  by  passing  through  sieves.  The  grains 
are  glazed  by  rotating  in  drums  with  or  without  graphite, 
which  gives  a  uniform  density  to  the  surface.  When  spe- 
cial forms  are  to  be  given  to  the  powder,  dies  are  used  to 
obtain  the  desired  shape ;  this  is  done  after  the  powder  has 
been  thoroughly  mixed  and  formed  into  press-cake. 


34  EXPLOSIVES  AND  DETONATORS 

Black  powder  or  gunpowder  is  used  in  primers,  fuses,  and 
also  in  the  cartridge  case  as  an  additional  priming  charge 
for  completing  the  combustion  of  the  propelling  charge.  In 
the  early  use  of  high-explosive  shells,  black  gunpowder  was 
also  used  as  a  bursting  charge,  but  in  recent  years  this  has 
been  supplemented  by  other  and  more  powerful  high-explo- 
sives. 

Smokeless  Powder.  —  The  modern  smokeless  powders 
are  put  up  into  many  forms,  but  all  have  the  same  base, 
namely  guncotton.  The  invention  of  guncotton  is  credited 
to  a  German  chemist  Schoenbein,  who,  in  1846,  discovered 
a  substance  that  he  called  "cotton  powder."  Improvements 
were  later  made  in  the  manufacture  of  guncotton  by  Gen- 
eral Von  Lenk  and  Sir  Frederick  Abel.  Two  of  the  prin- 
cipal smokeless  powders  are  nitrocellulose  and  nitrogly- 
cerine. While  the  base  of  these  is  guncotton,  the  final 
stages  in  their  manufacture  are  different;  for  instance,  in 
the  manufacture  of  nitroglycerine,  a  mineral  jelly  is  added. 

Manufacture  of  Guncotton.  —  In  the  manufacture  of 
guncotton,  the  short  fiber  of  the  cotton  that  is  detached  from 
the  cotton  seed  rather  late  in  the  process  of  removal  is  used. 
After  being  bleached  and  purified,  this  is  run  through  a 
picker  which  opens  up  the  fiber  and  breaks  up  any  lumps ; 
it  is  then  thoroughly  dried,  when  it  is  ready  for  nitration. 
The  most  generally  used  method  of  nitration  consists  in 
putting  the  cotton  into  a  large  vessel  nearly  filled  with  a 
mixture  of  nitric  and  sulphuric  acid.  The  sulphuric  acid 
is  used  to  absorb  the  water  developed  in  the  process  of 
nitration,  which  would  otherwise  dilute  the  nitric  acid  too 
much.  After  a  few  minutes  immersion,  the  pot  is  rapidly 
rotated  by  machinery  and  the  acid  permitted  to  escape.  In 
the  process  of  nitration,  the  cotton  has  not  changed  its  ap- 
pearance, but  has  become  a  little  harsh  to  touch.  The  ni- 
trated product  is  then  washed  in  a  preliminary  way,  re- 
moved from  the  nitrator,  and  repeatedly  washed  and  boiled 
to  remove  all  traces  of  free  acid.  The  keeping  qualities  of 
smokeless  powder  are  dependent  on  the  thoroughness  with 
which  it  is  purified.  At  this  stage  of  the  manufacture,  at 
least  five  boilings,  with  a  change  of  water  after  each  boil- 


EXPLOSIVES  AND  DETONATORS 


35 


ing,  covering  a  total  of  forty  hours,  is  necessary.  Follow- 
ing this  preliminary  purification,  the  cotton  is  cut  into  still 
shorter  lengths  by  being  repeatedly  run  between  cylinders 
carrying  revolving  knives.  This  operation  is  necessary,  as 


Fig.   16.     Boomer  &   Boschert  Guncotton   Press 

the  cotton  fibers  are  tubes,  making  it  difficult  to  remove  the 
traces  of  acid  from  the  interior  unless  they  are  of  very  short 
lengths.  After  being  pulped,  the  cotton  is  given  six  more 
boilings  with  a  change  of  water  after  each,  followed  by  ten 


36  EXPLOSIVES  AND  DETONATORS 

cold-water  washings.  The  completed  material  is  then 
known  as  guncotton  or  pyrocellulose. 

Before  adding  the  solvent  (acetone),  the  guncotton  must 
be  completely  freed  from  water.  This  is  partly  accom- 
plished in  a  centrifugal  wringer,  but  is  completed  by  com- 
pressing the  guncotton  into  a  solid  block  and  forcing  alcohol 
through  the  compressed  mass.  To  convert  the  guncotton, 
or  pyrocellulose,  into  nitrocellulose,  ether  is  added  to  the 
pyrocellulose  thus  impregnated  with  alcohol,  the  relative 
proportions  being  about  two  parts  of  ether  to  one  part  of 
alcohol,  by  volume.  After  the  ether  has  been  thoroughly 
incorporated  in  a  kneading  machine,  the  material  is  com- 
pressed into  blocks.  This  is  generally  accomplished  in  a 
hydraulic  press;  a  machine  especially  designed  for  this 
purpose  is  shown  in  Fig.  16.  This  press  is  built  by  the 
Canadian  Boomer  &  Boschert  Press  Co.,  Ltd.,  and  is  capable 
of  exerting  a  pressure  of  150  tons  on  the  material.  It  has 
three  sets  of  dies,  A,  B,  and  C,  which  are  held  on  a  separate 
column  on  the  press  upon  which  they  revolve ;  also  two  sets 
of  punches  or  male  dies,  one  set  D  being  used  for  pressing 
the  cotton  and  the  other  set  E  for  ejecting  it  after  pressing. 
The  base  of  the  machine  is  of  cast  iron,  through  which  a 
number  of  small  holes  are  drilled  to  allow  drainage  of  the 
water  from  the  cotton.  The  chief  advantage  of  this  press 
is  that,  being  provided  with  three  sets  of  dies,  it  is  possible 
to  load  one  set  of  dies  while  another  is  being  pressed,  and 
from  the  third,  the  cotton  is  ejected,  thereby  making  the 
operation  practically  continuous.  This  press  is  operated  by 
a  pump  giving  a  pressure  of  1500  pounds  per  square  inch. 

The  size  of  the  compressed  blocks  varies ;  in  some  cases, 
these  blocks  are  made  10  inches  in  diameter  by  15  inches 
long,  or  are  made  of  square  section.  In  this  operation,  the 
pyrocellulose  loses  the  appearance  of  cotton  and  takes  on 
a  dense  horny  appearance,  forming  what  is  known  as  a 
colloid.  The  colloid  is  then  transferred  to  a  finishing  press 
where  it  is  again  forced  through  dies  and  comes  out  in  the 
form  of  long  strips  or  rods,  which  are  cut  into  grains  of  the 
required  length.  The  grains  are  subjected  to  a  drying 
process,  which  removes  nearly  all  the  solvent  (acetone)  and 


EXPLOSIVES  AND  DETONATORS 


37 


leaves  the  powder  in  a  suitable  condition  for  use.  The  dry- 
ing process  is  a  lengthy  one,  taking  as  much  as  four  or  five 
months  for  the  larger  grain  powders.  Upon  completion, 
the  powder  is  blended  and  packed  in  air-tight  boxes. 

Cordite.  —  Cordite  is  the  form  in  which  smokeless  pow- 
der is  used  by  the  English  government  and  is  composed  of 
58  per  cent  nitroglycerine,  37  per  cent  guncotton,  and  5 
per  cent  vaseline.  The  vaseline  renders  the  powder  water- 
proof and  improves  its  keeping  qualities.  For  use  in  can- 
non, cordite  is  made  into  long  thick  rods  that  are  tubular 
in  form  or  in  the  form  of  perforated  cylinders;  for  heavy 
guns,  a  powder  called  cordite  M.  D.  has  lately  been  intro- 
duced ;  this  composition  consists  of  30  parts  nitroglycerine, 
65  parts  guncotton,  and  5  parts  vaseline.  The  reduction  in 


Ma-oJiinery 


Fig.  17.     Form  and  Size  of  Grain  for  Smokeless  Powders 

the  percentage  of  nitroglycerine  was  necessary  because 
of  the  desire  to  lower  the  temperature  of  the  explosive 
and  the  consequent  erosion  in  the  bore  of  the  gun. 

Forms  of  Smokeless-powder  Grains. —  The  form  of  grain 
in  which  smokeless  powder  is  made  differs  in  various  coun- 
tries. In  foreign  countries,  especially  in  Germany,  nitro- 
cellulose in  the  form  of  long  tubes  similar  in  shape  to  maca- 
roni are  used.  Fig.  17  shows  a  few  of  the  many  forms  in 
which  smokeless  powder  is  put  up.  A  shows  a  tube,  which 
is  sometimes  two  feet  long;  usually,  however,  the  nitro- 
cellulose when  put  up  in  this  form  is  about  the  length  of 
the  chamber  in  the  gun  or  long  enough  to  about  fill  the 


38  EXPLOSIVES  AND  DETONATORS 

cartridge  case.  Another  way  in  which  nitroglycerine 
smokeless  powder  is  put  up  is  the  slab  form  shown  at  B. 
In  cartridges  used  by  the  French  government,  this  slab  is 
0.0195  inch  thick,  i/£  inch  wide,  and  about  from  5  to  6  inches 
long.  This  form  of  smokeless  powder  is  also  used  by  the 
Italian  government.  In  the  United  States  Army  service, 
the  nitrocellulose  powder  is  put  up  in  the  form  of  cylindri- 
cal grains,  as  shown  at  C  and  D,  which  are  provided  with 
seven  longitudinal  perforations,  one  central  and  the  other 
six  equally  distributed  midway  between  the  center  of  the 
grain  and  its  circumference.  A  uniform  thickness  of  web 
is  thus  obtained.  The  length  and  diameter  of  the  grain 
vary  in  powders  for  different  guns,  the  size  increasing  with 
the  caliber  of  the  gun.  The  length  is  unimportant,  the  web 
between  the  perforations  being  the  factor  that  receives  first 
attention.  For  the  3-inch  rifle,  the  grain  has  a  length  of 
about  %  inch  and  a  diameter  of  0.195  inch,  as  shown  at  D. 
For  the  12-inch  rifle,  the  length  is  1%  inch  and  the  diame- 
ter %  inch,  as  shown  at  C.  For  smaller  guns,  the  grains 
are  in  the  form  of  thin  flat  squares,  as  shown  at  E.  When 
used  in  howitzers  or  mortars,  smokeless  powder  is  put  up 
sometimes  in  the  form  of  tubes,  solid  and  tubular  rods,  flat 
disks,  and  rolled  sheets. 

High-explosives  or  Shell  Fillers.  —  High-explosives,  which 
are  generally  termed  "shell  fillers,"  are  known  by  various 
trade-names;  such  as  emmensite,  lyddite,  melenite,  maxim- 
ite,  nitrobenzole,  nitronaphthaline,  shimose,  trinitroto- 
luol, etc.  The  base  of  such  explosives  as  emmensite,  max- 
imite,  lyddite,  melenite  and  shimose  is  picric  acid,  which  is 
secured  from  coal  tar  subjected  to  fractional  distillation. 
The  liquid  that  comes  off  when  this  is  raised  to  a  tempera- 
ture of  302  degrees  F.  (150  degrees  C.)  is  called  "light" 
oil,  and  when  these  light  oils  have  been  again  distilled,  the 
next  fraction  or  "middle"  oil  is  phenol  or  carbolic  acid ;  this 
substance  when  nitrated  gives  off  picric  acid,  or,  as  it  is 
sometimes  called,  trinitrophenol.  As  a  shell  filler,  this  ex- 
plosive may  be  pressed  into  the  explosive  cavity  or  melted 
and  poured  in.  It  forms  an  unstable  metallic  salt  when 
coming  in  contact  with  the  body  of  the  shell,  and,  conse- 


EXPLOSIVES  AND  DETONATORS  39 

quently,  when  assembling  or  when  pouring  the  melted  acid 
in  the  shell,  it  is  necessary  to  first  coat  the  cavity  thoroughly 
with  a  non-metallic  paint.  Picric  acid  is  the  basis  of  many 
of  the  foreign  shell  fillers.  The  difference  in  composition 
of  these  various  explosives  usually  consists  in  the  addition 
of  an  ingredient  (camphor,  nitronaphthaline,  trinitroto- 
luene, etc.)  which  are  introduced  to  reduce  the  melting 
point. 

At  present,  the  most  popular  or  generally  used  shell 
filler  is  T.  N.  T.  (trinitrotoluol).  Although  the  explosive 
force  of  trinitrotoluol  is  somewhat  less  than  that  of  picric 
acid,  the  pressure  of  the  latter  being  about  135,820  pounds 
per  square  inch,  as  against  119,000  pounds  for  trinitroto- 
luol, its  advantages  more  than  compensate  for  the  differ- 
ence. Trinitrotoluol  is  obtained  by  the  nitration  of  toluene 
obtained  from  crude  benzol  distilled  from  coal  tar  and 
washed  out  from  coal  gas.  The  crude  benzol  contains 
roughly : 

Constituent  Per  Cent 

Benzine    50 

Toluene    36 

Xylene   11 

Other  Substances 3 

Toluene,  to  be  used  for  the  manufacture  of  trinitrotoluol, 
should  be  a  clear  water-like  liquid,  free  from  suspended 
solid  matter,  and  having  a  specific  gravity  not  less  than 
0.868  nor  more  than  0.870,  at  about  59  degrees  F.  (15.5 
degrees  C.).  Trinitrotoluol,  when  pure,  has  no  odor  and  is 
a  yellowish  crystalline  powder  which  darkens  slightly  with 
age.  It  cannot  be  exploded  by  flame  or  strong  percussion 
and  a  rifle  bullet  may  be  fired  through  it  without  any  effect. 
When  heated  to  356  degrees  F.  (180  degrees  C.),  it  ignites 
and  burns  with  a  heavy  black  smoke;  but  when  detonated 
by  a  fulminate-of -mercury  detonator,  it  explodes  with  great 
force,  giving  off  a  black  smoke.  Shells  containing  this  ex- 
plosive first  used  on  the  Western  battlefront  were  given 
such  names  as  "coal-boxes,"  "Jack  Johnson,"  "Black 
Maria's,"  etc.,  by  the  Allies. 


40  FULMINATES  AND  CHLORATES 

In  the  United  States  service,  picric  acid,  explosive  "D," 
and  trinitrotoluol  are  used  as  shell  fillers.  High-explosive 
shells  containing  explosive  "D"  with  a  small  charge  of  picric 
acid  surrounding  the  detonator  are  used,  and  in  high-explo- 
sive shrapnel,  trinitrotoluol  is  used  as  a  matrix.  Trinitro- 
toluol may  also  be  detonated  with  a  fulminate-of-mercury 
detonator  augmented  by  a  small  amount  of  trinitrotoluol  in 
loose  crystals. 

The  Russians  and  Austrians  use  a  high-explosive  known 
as  ammonal,  in  which  from  12  to  15  per  cent  of  trinitrotoluol 
is  mixed  with  an  oxidizing  compound,  ammonium  nitrate,  a 
small  amount  of  aluminum  powder  and  a  trace  of  charcoal. 
This  high-explosive  gives  somewhat  better  results  than 
plain  trinitrotoluol,  but  has  the  one  disadvantage  of  easily 
collecting  moisture,  and  must  be  made  up  in  air-tight  car- 
tridges. The  British  are  now  using  an  improved  compound 
of  this  character,  which  is  so  prepared  that  trouble  is  not 
experienced  with  the  collection  of  moisture. 

Fulminates  and  Chlorates.  —  The  action  of  fulminates  is 
more  powerful  than  either  the  low-  or  high-explosives  de- 
scribed. They  can  be  readily  detonated  by  slight  shock 
or  by  the  application  of  heat  and  are  used  in  primers  for 
setting  off  the  propelling  charge  in  the  cartridge  case,  and 
in  fuses,  either  of  the  plain  percussion  or  combination  time 
and  percussion  types.  The  most  common  fulminate  is 
made  by  dissolving  mercury  in  strong  nitric  acid  and  then 
pouring  the  solution  into  alcohol.  After  an  apparently 
violent  reaction,  a  mass  of  fine,  gray  crystals  of  fulminate 
of  mercury  is  produced.  The  crystalline  powder  thus  pro- 
duced is  washed  with  water  to  free  it  from  acid,  and  is  then 
mixed  with  glass  ground  to  a  fine  powder.  Because  of  its 
extreme  sensitiveness  to  heat  produced  by  the  slightest  fric- 
tion, it  is  usually  kept  in  water  or  alcohol  until  needed. 

A  common  mixture  of  fulminate  of  mercury  for  use  in 
primers  contains  the  following  ingredients  : 

Ingredients  Per  Cent 

Fulminate  of  Mercury 50 

Chlorate  of  Potassium 20 

Glass   (ground) 30 


FULMINATES  AND   CHLORATES  41 

The  ground  glass  must  be  sifted  through  a  sieve  having 
100  meshes  to  the  linear  inch.  To  the  mixture  given  is  added 
0.25  per  cent  of  tragacanth  gum  and  a  trace  of  gum  arabic. 
This  composition  is  placed  in  the  primer  while  moist;  after 
compression,  the  primer  cap  is  dried  for  ten  days  at  a  tem- 
perature of  88  degrees  F.  (about  31  degrees  C.),  and  for 
twelve  days  at  111  degrees  F.  (about  44  degrees  C.).  Then 
the  exterior  surface  of  the  parchment  covering  the  mixture 
is  coated  with  a  thick  varnish  composed  of  0.891  gallon  of 
95  per  cent  alcohol,  2.75  pounds  of  shellac,  and  0.5  pound 
resin.  The  varnished  primers  are  dried  at  a  room  tempera- 
ture for  five  or  six  days. 

In  primers  used  in  British,  American,  and  some  of  the 
foreign  cartridge  cases,  the  fulminate-of -mercury  detonator 
is  replaced  by  chlorate  of  potassium.  The  resulting  com- 
position is  less  dangerous  to  handle  than  when  ful- 
minate of  mercury  is  used,  and  also  has  much  less  erosive 
effect  on  the  bore  of  the  gun. 


CHAPTER  III 
FORGING  HIGH-EXPLOSIVE  SHELLS 

AT  present,  the  preliminary  stages  in  the  manufacture  of 
high-explosive  shell  forgings  are  carried  on  in  one  of  two 
ways :  The  first  is  to  use  hot-drawn  bar  stock  cut  up  into 
billets  of  the  required  length  in  cutting-off  or  shearing 
machines;  the  second  is  to  cast  billets,  varying  in  length 
and  diameter,  depending  on  the  size  of  the  shell.  These  bil- 
lets are  then  cut  up  into  blanks  of  the  required  lengths  for 
forging. 

In  one  of  the  prominent  Canadian  plants  engaged  in  this 
work,  billets  for  British  4.5  high-explosive  shells  are  cast 
in  ingot  molds  to  33  inches  in  length  by  4  15/16  inches 
in  diameter.  Following  the  casting,  the  billets  are 
thrown  down  into  the  sand  and  allowed  to  cool  off. 
Next,  the  billets  are  cut  into  sections  9-^  inches  long, 
the  bar  being  partly  severed  at  the  required  points  and 
then  taken  out  of  the  lathe  and  broken.  The  teats  are  fin- 
ally cut  off  on  a  planer,  leaving  the  blanks  in  a  suitable  con- 
dition for  forging.  When  the  forgings  are  made  from 
bar  stock,  cut  off  from  hot-rolled  bars,  the  high-power  cut- 
ting-off  machine  is  generally  used. 

Forging  British  4.5  High-explosive  Shell  Blanks.  —  Sev- 
eral methods  have  been  used  in  the  Canadian  plants  in 
forging  high-explosive  shell  blanks.  One  prominent  con- 
cern, in  the  early  stages  of  this  work,  adopted  the  method 
shown  in  Fig.  18  for  forging  4.5  high-explosive  shell  blanks. 
A  blank  4  13/16  inches  in  diameter  by  9  inches  long  was 
heated  in  a  furnace  to  1950  degrees  F.  (about  1070  degrees 
.C.)  for  about  45  minutes  and  then  taken  out  and  dropped 
into  the  die  a  shown  at  A,  Fig.  18.  One  operator  then 
quickly  placed  the  guide  b  over  the  die  and  put  in  the  punch 

42 


FORGING  SHELLS 


43 


Fig.  18.     Three-operation  Method  of  making  4.5  British 
High- explosive  Shell   Forgings 


44 


FORGING   SHELLS 


c,  which  a  steam  hammer  started  into  the  billet.  When 
the  punch  had  been  driven  in  far  enough  to  get  a  good 
start,  it  was  removed,  cooled  in  water,  the  guide  b  removed, 
the  punch  replaced,  and  three  or  four  blows  delivered,  fin- 
ishing the  billet  as  shown  at  B.  The  billet  was  again  heated 
to  the  correct  temperature,  placed  in  the  die,  as  shown  at  C, 
and  drawn  up  to  the  shape  shown  at  D  by  one  stroke  of  a 
hydraulic  press  of  500  tons'  capacity.  A  final  forging  or 
drawing  operation  was  then  accomplished  by  forcing  the 


Machinery 


Fig.   19.     One-operation   Method  of  making  4.5   British   High- 
explosive  Shell    Forgings 

forging  through  two  dies  that  are  5  1/16  and  4  15/16  inches 
in  diameter,  respectively,  as  shown  at  E  and  F.  The  forg- 
ing as  completed  was  4%  inches  in  diameter,  by  12%  inches 
long,  with  a  base  11/2  inch  thick.  After  the  forgings 
were  removed  from  the  die,  they  were  allowed  to  cool,  after 
which  they  were  inspected. 

Later  Method  of  Forging  British  Shell  Blanks.  —  The 
method  just  described  has  been  improved  by  the  concern 
using  it;  the  new  method  is  illustrated  in  Figs.  19  and  20. 
In  Fig.  20  is  shown  the  350-ton  hydraulic  press  used  to 


FORGING   SHELLS 


45 


complete  the  forging  in  one  "shot."  The  billet,  as  shown  in 
Fig.  19,  is  4.8  inches  in  diameter  and  91/2  inches  long.  This 
is  cut  off  from  a  cast  billet  and  placed  in  a  furnace  heated 
by  fuel  oil  until  it  reaches  a  temperature  of  about  from  1900 
to  1950  degrees  F.  (about  from  1040  to  1070  degrees  C.) .  It 


Fig.    20. 


Forging    British    4.5    High-explosive    Shells    in    One 
Operation 


is  then  pulled  out  by  a  long  bar  with  a  bent  end,  dropped  on 
to  a  sheet-iron  slide,  and  carried  over  near  the  hydraulic 
press.  Here  it  is  quickly  picked  up  by  one  of  the  operators 
and  placed  on  a  block,  where  all  the  excessive  scale  is  re- 
moved by  means  of  a  scoop.  It  is  then  dropped  into  the 


46  FORGING  SHELLS 

die  and  the  press  operated.  In  this  particular  case,  no 
bushing  or  guide  is  used  to  center  the  punch,  which  is  al- 
lowed to  descend  freely  into  the  heated  billet,  extruding 
it  around  the  punch.  The  punch  and  die  are  kept  lubri- 
cated with  a  mixture  of  graphite  and  oil  and  are  also  cooled 
by  a  stream  of  water  after  each  billet  has  been  pierced. 
In  this  operation,  the  forging  is  drawn  out  in  one  "shot" 
from  9V£  to  13%  inches  in  length;  sometimes  it  even  ex- 
ceeds 14  inches.  The  shape  of  the  die  and  the  size  and 
shape  of  the  finished  forging  are  shown  at  B,  Fig.  19.  The 
production  on  this  operation  is  220  in  eight  hours,  and  four 


Fig.   21.     Cutting   off    Blanks   for    Russian    3-inch    High- 
explosive  Shell  Forgings  in  a  Shearing  Press 

men  are  required,  three  to  attend  to  the  press  and  one  to  the 
furnace. 

Forging  Russian  3-inch  High-explosive  Shell  Blanks.  - 
A  very  complete  and  interesting  forging  equipment  is  used 
by  the  Laconia  Car  Co.,  Laconia,  N.  H.,  for  turning  out 
3-inch  Russian  shrapnel  forgings  at  the  rate  of  3000  per 
day.  In  this  plant,  the  bulldozer  is  used  for  performing 
both  the  piercing  and  drawing  operations  on  the  forgings. 
Russian  high-explosive  shell  forgings  are  made  from  steel 
containing  50-point  carbon  and  are  also  high  in  manganese. 
Great  difficulty  has  been  experienced  in  cutting  these  bars 


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48  FORGING  SHELLS 

After  cutting  off,  the  billets  are  placed  in  a  furnace  of  the 
type  shown  in  Fig.  22,  which  has  been  built  especially  for 
this  work  by  this  company;  here  the  blanks  are  heated  to 
2250  degrees  F.  (about  1230  degrees  C.).  These  furnaces 
are  of  the  open-hearth  down-draft  type,  built  to  the  dimen- 
sions given  in  the  illustration.  The  heating  space  is  18 
inches  at  the  highest  point  of  the  arc,  and  3  feet  wide  by 
5  feet  6  inches  long.  Each  furnace  is  provided  with  two 
double  burners,  and  i/2-pound  air  pressure  from  a  Sturte- 
vant  fan  is  sufficient  to  operate  them.  In  maintaining  a 
temperature  of  2250  degrees  F.,  only  9  gallons  of  crude  oil 


Fig.    23.     Arrangement    of    Dies    and    Punches    on    Williams    & 
White  Bulldozer  for  forging  Russian   High-explosive  Shells 

is  consumed  per  hour  by  each  furnace.  With  these  fur- 
naces, a  temperature  of  2850  degrees  F.  (about  1570  de- 
grees C.)  can  be  obtained  without  trouble,  but  the  tempera- 
ture required  for  this  work  seldom  exceeds  2300  degrees 
F.  (about  1260  degrees  C.). 

Forging  Machine.  —  The  forging  is  done  on  a  Williams  & 
White  size  9-U  bulldozer,  as  shown  in  Fig.  23.  This  ma- 
chine is  capable  of  making  six  strokes  per  minute  and  a 
forging  is  completed  in  two  strokes ;  the  piercing  and  draw- 
ing operations  are  carried  on  at  the  same  time.  The  pierc- 
ing punches  and  dies  shape  the  piece,  as  shown  at  B,  Fig. 


FORGING  SHELLS 


49 


24,  whereas  the  drawing  punches  and  dies  complete  the 
forging  as  shown  at  C.  The  piercing  and  drawing  dies 
are  held  in  a  special  holder  fastened  to  the  bed,  whereas 
the  punches  are  held  on  the  cross-head.  The  two  outer 
punches  at  each  side,  A,  B,  C,  and  D  are  the  drawing 
punches,  and  the  four  inner  ones  E,  G,  H,  and  I  are  for 
piercing.  There  are  seven  men  in  the  forging  team  for 
each  machine:  One  attends  to  the  furnace,  one  removes 
the  forgings  from  the  furnace,  and  one  starts  and  stops  the 
bulldozer  and  looks  after  the  machine;  on  each  side  of  the 
machine  there  are  two  tool-men  and  two  forgers. 


2  TMDS.  PER  INCH  R.H. 


Fig.  24.     Russian  3-inch   High-explosive  Shell  from  the  Blank 
to  the   Finished   Shell 

The  method  of  operation  is  as  follows:  The  forge-man 
gets  the  hot  billet  from  the  furnace-man  and  puts  it  in  one 
of  the  two  piercing  dies  on  his  side  of  the  machine ;  one  blow 
partly  forms  it.  He  then  passes  it  on  to  one  of  the  two 
drawing  punches  at  his  side,  the  tool-man  swinging  the 
punch  up  to  permit  the'  forging  to  be  removed  and  at  the 
same  time  greases  the  punch.  The  object  of  having  two 
piercing  and  two  drawing  punches  is  to  allow  one  to  cool 
while  the  other  is  being  used,  the  two  sides  of  the  machine 
being  used  alternately. 


50 


FORGING   SHELLS 


Fig.  23  shows  clearly  how  the  punches  and  dies  are 
held.  The  piercing  punches  are  shorter  than  the  drawing 
punches  and  pass  through  the  strippers  K,  which  remove 
the  pierced  forging  from  the  punch,  as  the  forging  is  not 
forced  through  the  die  when  being  pierced.  The  strippers 
are  operated  by  the  V-shaped  members  /,  which  come  be- 
tween them  and  close  them  in  on  the  punch. 

The  piercing  punches  are  made  from  special  vanadium 
steel,  and  5000  forgings  are  made  before  the  punches  are 
worn  out.  The  drawing  punches  are  also  made  from  vana- 


Fig.  25.     Method  of  Forging  Large-caliber  High-explosive  Shells 

dium  steel  and  turn  out  about  3000  blanks  before  giving 
out.  For  the  dies,  white  cast  iron  is  used,  and  4000  blanks 
is  the  limit  obtained  from  one  die.  The  drawing  dies  are 
made  of  chilled  cast  iron  and  last  from  1800  to  2000  forg- 
ings. The  forgings  are  not  annealed,  but  are  allowed  to 
cool  slowly  in  sand.  One  team  of  men  and  one  machine  will 
produce  500  forgings  in  eight  hours  without  any  trouble. 


FORGING   SHELLS 


51 


Forging  Large-caliber  Shell  Blanks. —  At  present,  there 
are  two  principal  methods  of  making  large  high-explosive 
shell  blanks.  One  of  these  does  not  differ  materially  from 
that  used  in  the  production  of  forgings  for  medium-caliber 
shells.  In  the  large-caliber  shells,  the  hole  in  the  nose,  when 
the  shell  carries  a  nose  fuse,  is  small  in  proportion  to  that 
used  in  the  small-caliber  forgings.  Consequently,  a  greater 
amount  of  metal  is  turned  in  at  the  nose. 

One  method  of  making  these  shells  is  shown  in  Fig.  25. 


C      Machinery 


Fig.  26.     Diagram  illustrating  Method  of  Forging  Armor-piercing 
Shells 

The  preliminary  stages  in  the  process,  shown  by  the  dia- 
gram at  A,  B,  C,  D,  and  E,  are  the  same  as  for  making  an 
ordinary  forging.  For  instance,  the  billet  is  pierced,  as 
shown  at  A,  B,  and  C,  by  being  forced  over  punch  d  by 
punch  c  acting  through  die  a.  The  frame  carrying  die- 
holder  b  then  rises,  and  stripper  plate  e  removes  the  pierced 
forging  from  the  punch,  as  shown  at  D.  The  next  step 
consists  in  drawing  the  pierced  forging  through  dies,  as 
shown  at  E.  The  forging  is  then  heated  on  the  nose  end, 


52  FORGING  SHELLS 

taken  to  another  press  and  dropped  into  a  die,  as  illustrated 
at  F.  The  nosing-in  punch  then  descends,  as  shown  at  G, 
and  closes  in  the  open  end  of  the  forging  to  the  shape 
shown  at  H.  Further  operations  consist  in  drilling  out  the 
nose  for  the  fuse,  and  threading  it,  etc.,  for  the  reception  of 
the  fuse.  In  this  class  of  forging,  no  machining  whatever 
is  done  in  the  cavity  of  the  shell. 

A  method  of  making  large-caliber  shell  f orgings  that  are 
open  both  on  the  nose  and  the  base  ends  is  to  use  seamless 
drawn  tubing.  The  operation  consists  in  cutting  a  piece 
of  tubing  to  the  required  length,  heating  one  end,  and  plac- 
ing the  tubing  in  a  hydraulic  press,  where,  by  means  of  a 
properly  shaped  die  and  punch,  the  base  end  is  upset  in 
toward  the  center.  The  forging  is  then  heated  on  the 
opposite  end,  placed  in  another  press,  and  nosed-in  in  a 
manner  similar  to  that  shown  at  G,  Fig.  25.  This  method 
of  making  large  forgings  has  the  advantage  of  saving  con- 
siderable material,  both  in  the  preliminary  stages  and  in 
the  final  machining  operations. 

Forging  Armor-piercing  Shells. —  Armor-piercing  shells 
are  always  made  with  a  solid  nose,  as  this  type  of  shell  is 
used  for  piercing  hardened  armor,  which  calls  for  great 
strength  in  the  nose.  One  method  of  making  armor-pierc- 
ing shells,  which  is  also  applicable  to  the  production  of  the 
type  of  high-explosive  shell  used  by  the  United  States  gov- 
ernment, is  shown  in  Fig.  26.  This  method  does  not  differ 
in  principle  from  that  shown  in  Fig.  19,  except  that  the  shell 
is  forged  with  the  nose  instead  of  the  base  down.  Usually, 
the  punch  is  not  relied  upon  to  center  in  the  billet  accu- 
rately, so  a  centering  bushing  is  used.  The  bushing  is  in- 
serted in  the  top  of  the  die,  the  punch  is  allowed  to  descend 
for  a  short  distance  into  the  heated  billet  and  is  then  raised ; 
the  bushing  is  then  removed  and  the  punch  again  advanced. 
When  making  a  forging  in  the  manner  shown  in  Fig.  26, 
it  is  usually  necessary  to  eject  the  forging  and  make  it  fol- 
low the  punch,  from  which  it  is  removed  by  a  stripper  as  the 
punch  rises. 


CHAPTER  IV 


MACHINING  BRITISH  18-POUND  SHELLS 

A  VARIETY  of  methods  are  used  in  machining  the  British 
18-pound  (3.29-inch)  high-explosive  shell  shown  in  Fig.  27. 
In  the  greater  number  of  cases,  however,  the  shell  is  ma- 
chined from  bar  stock.  One  of  the  two  principal  methods 
used  in  machining  from  bar  stock,  outlined  in  Table  I,  con- 
sists in  cutting  up  bars  of  hot-drawn  stock  into  billet 
lengths,  which  are  then  drilled  and  reamed,  and  afterwards 
turned,  etc.  The  other,  while  similar  in  the  final  opera- 
tions, starts  with  turning.  A  bar  generally  sixteen  feet 


i^   >|^  . ^ 

|U0.77|  HQ.915I 
L0.73    L0.880 


Machinery 


Fig.  27.     British   18-pound   High-explosive   Shell 

long  is  centered  on  both  ends,  then  put  in  the  lathe  and 
turned  down  to  approximately  the  finished  size.  After  this, 
it  is  cut  up  into  shell  lengths,  drilled,  reamed,  threaded,  etc. 
Cutting  off  18-pound  Shell  Blanks.  —  Many  methods  are 
used  for  cutting  off  shell  blanks ;  usually,  however,  several 
blanks  are  cut  off  at  one  time.  The  Earle  Gear  &  Machine 
Co.  has  devised  a  fixture  for  the  Lea-Simplex  cold  saw  by 
means  of  which  nine  bars  can  be  cut  off  at  one  setting.  The 
average  cutting  time  for  nine  bars  is  nine  minutes,  and  the 
production  on  314 -inch  bars  is  about  sixty  per  hour. 

53 


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54 


MACHINING  BRITISH   SHELLS 


55 


Drilling  and  Reaming.  —  After  cutting  off,  the  first  opera- 
tion, rough-drilling,  is  usually  performed  in  a  high-power 
drilling  machine,  as  shown  in  Fig.  28.  The  shell  blank  is 
held  in  a  special  fixture,  shown  in  Fig.  29,  consisting  of  two 
jaws  operated  by  left-  and  right-hand  screws  by  means  of 
handwheel  A.  The  top  of  the  fixture  is  of  yoke  form  and 


Fig.  28.     Baker   High-power   Drilling    Machine  at  Work  on   British 
18-pound  High-explosive  Shells 

carries  the  drill-guiding  bushing  B.  In  this  particular  case, 
the  drilling  is  done  with  a  "Hercules"  1  13/16-inch  drill, 
rotated  at  115  R.  P.  M.  and  fed  down  into  the  work  at  a 
feed  of  0.017  inch  per  revolution  of  the  drill.  The  hole 
drilled  is  8%  inches  deep,  and  the  production  is  nine  per 


56 


MACHINING  BRITISH   SHELLS 


hour.  To  start  the  drill  central  with  the  blank,  a  bushing 
is  slipped  into  the  top  of  the  jig,  but  when  the  drill  has 
once  started  properly  this  is  removed.  The  second  opera- 
tion consists  in  rounding  the  bottom,  that  is,  removing  the 
vee  left  by  the  end  of  the  drill.  This  is  done  with  a  coun- 
terboring  tool  rotated  at  115  R.  P.  M.  and  fed  down  by 
hand.  The  machine  used  is  a  Baker  high-power  drilling 


Machinery 


Fig.  29. 


Fixture  used  in   Holding  18-pound  Shell   Blanks  when 
Drilling 


machine  and  the  production  is  thirty  per  hour.  The  third 
operation  consists  in  reaming  the  hole  to  1.885  inch  in 
diameter  with  a  reamer  rotated  at  115  R.  P.  M.  and  fed  at 
the  rate  of  0.032  inch  per  revolution  to  8  15/16  inches  deep ; 
the  production  is  twelve  per  hour. 

Turning  Band  Groove,  Waving,  etc.  —  The  fourth  opera- 
tion is  performed  on  a  No.  2-A  Warner  &  Swasey  turret 


MACHINING  BRITISH    SHELLS 


57 


lathe  in  the  order  shown  by  the  diagram,  Fig.  30.  This 
consists  first  in  rough-turning  the  external  diameter  with  a 
box-tool  A  for  a  distance  of  about  6%  inches  from  the  base 
end  and  removing  %  inch  from  the  diameter  at  a  feed  of 
0.041  inch  per  revolution  of  the  work;  second,  boring  the 
gas-plug  recess,  facing  the  end,  and  turning  and  forming 
the  radius  with  tool  B;  third,  rough-forming  the  band 
groove  with  tool  C;  fourth,  finish-facing  the  plug  recess 
and  end  with  tool  D;  fifth,  forming  waves  in  the  band 


2ND  OPERATION 

BORE,   FACE,   TURN  AND 

FORM  RADIUS 


/  OPERATION 
ROUGH  TURN 


3RD  OPERATION 
FORM  BAND  GROOVE 


4TH  OPERATION 

FINISH  FACE  RECESS 

AND  END 


TH  OPERATION 
FINISH  BORE, 
COUNTERBORE, 
AND  CHAMFER 


5TH  OPERATION 
FORM  WAVES  IN 
BAND  GROOVE 


7TH  OPERATION 

UNDERCUT 
BAND  GROOVE 


Machinery 


Fig.  30. 


Diagram  showing  Set-up  for  performing  External  Turn- 
ing, Facing  and  Waving  Operations 


groove  from  the  cross-slide  with  tool  F;  sixth,  finish-boring, 
counterboring,  and  chamfering  the  plug  recess  with  tool  G; 
seventh,  under-cutting  the  band  groove  with  tool  H.  The 
waving  is  done  from  the  cross-slide  and  at  the  same  time  the 
work  is  supported  by  a  roller  support  from  the  turret.  For 
the  finishing  cuts,  the  work  is  rotated  at  187  R.  P.  M.,  and 
the  production  is  from  six  and  one-half  to  seven  per  hour. 

Rough-turning,  Facing,  etc.  —  The  fifth  operation   con- 
sists in  rough-turning  the  nose  in  a  Reed-Prentice  20-inch 


58 


MACHINING  BRITISH    SHELLS 


engine  lathe,  as  shown  in  Fig.  31,  with  a  single  tool  operat- 
ing at  a  feed  of  0.071  inch  per  revolution,  and  with  the 
work  revolving  at  56  R.  P.  M.  The  shell  is  held  in  a  special 
draw-in  collet  A  that  is  supported  by  a  steadyrest,  as  shown. 
Three  cuts  are  required  to  finish  the  nose  of  the  shell  to 
form,  the  tool  being  controlled  in  its  movement  by  a  cam  lo- 
cated at  the  rear  of  the  machine.  The  production  is  from 
twelve  to  fourteen  per  hour. 

The  sixth  operation  is  performed  on  a  No.  2-A  Warner  & 
Swasey  turret  lathe,  as  shown  in  Fig.  32.  In  this  set-up 
the  shell  is  rough-faced  to  length  and  the  clearance  angle 


Fig.  31.     Rough-turning  Nose  in  an  Engine  Lathe 

cut  on  the  nose.  The  recess  is  then  cut  at  the  bottom  of 
the  thread  with  recessing  tool  A  and  the  hole  reamed  for 
threading  to  1.906  inch  in  diameter,  1.2  inch  deep,  with  tool 
B.  A  light  cut  is  taken  across  the  radius  on  the  nose  with 
tool  C  which  carries  a  roller  pilot  and  is  operated  from  the 
cross-slide.  The  work  is  rotated  at  78  R.  P.  M.  for  the  pro- 
filing or  the  radius  cut  at  a  feed  of  0.058  inch  per  revolu- 
tion. The  feed  is  reduced  to  0.028  inch  per  revolution  for 
reaming.  The  production  is  fifteen  to  seventeen  per  hour. 

Finish-turning.  —  The  seventh  operation  consists  in  fin- 
ish-turning from  the  band  groove  to  the  nose  on  an  F.  E. 


MACHINING  BRITISH    SHELLS 


59 


Reed  18-inch  engine  lathe,  as  shown  in  Fig.  33.  Here  the 
cross-feed  screw  has  been  removed  and  the  movement  of 
the  cross-slide  is  controlled  by  a  former  at  the  rear.  The 
shell  is  held  at  the  closed  end  by  a  two-jaw  chuck,  and  lo- 


ng. 32.     Performing  Sixth  Operation  on  a  2-A  Warner  &  Swasey 
Turret  Lathe 


Fig.  33.     Finish-turning   External   Diameter  on  an   Engine   Lathe 

cated  by  a  stop-screw  A;  a  plug  is  screwed  into  the  open  end 
and  is  supported  on  the  tailstock  center.  The  work  is  ro- 
tated at  100  R.  P.  M.  and  the  feed  is  3/64  inch  per  revolu- 


60 


MACHINING  BRITISH   SHELLS 


tion.  One  man  runs  two  machines  and  the  production  is 
twelve  to  fifteen  per  hour  from  each  machine. 

Counterboring,  Making  Screw  Holes,  etc. — The  eighth 
operation  is  to  counterbore  and  drill  the  grub-screw  hole  A, 
Fig.  27,  in  the  nose  of  the  shell  for  fastening  the  fuse  in 
place.  The  ninth  operation  on  the  shell  consists  in  tapping 
the  screw  hole  with  a  Peter  Bros,  tap  chuck  held  in  a  Barnes 
drill.  It  requires  two  taps  to  finish  this  hole  and  they  are 
operated  at  40  R.  P.  M. ;  the  production  is  forty  per  hour. 

The  tenth  operation  is  to  face  the  recess  in  the  cavity  in 
the  base  end  of  the  shell  where  the  gas  plug  is  to  be  in- 
serted. This  is  performed  in  a  Fay  &  Scott  16-inch  engine 


Fig.  34.     Threading  Nose  and  Base  Ends  of  Shell  in  Holden- Morgan 
Special  Thread  Milling  Machines 

lathe,  and  one  cut  is  taken  with  a  tool  held  in  a  special 
holder.  The  tool  is  started  at  the  outside  of  the  recess  and 
works  in  toward  the  center.  The  work  is  rotated  at  180 
R.  P.  M.  and  the  feed  is  1/32  inch  per  revolution;  the  pro- 
duction is  forty  per  hour. 

Threading  Nose  and  Base  Ends.  —  The  eleventh  opera- 
tion consists  in  threading  the  nose  of  the  shell  in  a  Holden- 
Morgan  thread  milling  machine,  as  shown  in  Fig.  34.  A 
hob  similar  in  construction  to  that  described  in  connection 
with  Fig.  35  is  used  for  cutting  the  thread,  and  one  revolu- 
tion of  the  work  completes  the  thread,  which  requires  1.10 
minute.  The  production  is  twenty  per  hour  from  each  ma- 


MACHINING  BRITISH    SHELLS 


61 


chine,  one  operator  attending  to  two  machines.  The  twelfth 
operation  consists  in  recessing  and  threading  the  base  end 
of  the  shell  in  a  Holden-Morgan  threading  machine  of  the 
same  type  as  those  shown  in  Fig.  34.  Here  one  man  also 
runs  two  machines,  one  being  set  up  for  recessing  and  the 
other  for  threading.  The  production  is  130  in  ten  hours 
from  the  two  machines.  The  thirteenth  operation  consists 
in  washing  the  shells  in  hot  soda  water,  after  which  they 
are  inspected. 

Machining  the  Gas  Plug.  —  Before  any  other  operations 
are  performed  on  the  shell,  the  gas  plug  B,  Fig.  27,  is  made 


Fig.  35.     Machining  Gas  Plugs  on   Holden-Morgan  Special   Plug 
Machine 

from  a  forging  and  is  faced,  turned,  and  threaded  on  the 
Holden-Morgan  special  plug  milling  and  threading  machine 
shown  in  Fig.  35.  The  plug  is  held  by  the  tail  in  a  special 
draw-in  chuck.  The  first  operation  is  to  rough-turn  and 
face  the  end  of  the  plug,  two  cuts  being  taken.  The  tools 
used  are  located  one  behind  the  other  in  a  tool-holder  A 
that  is  fastened  to  the  front  of  the  cross-slide  operated  by 
the  handwheel  B.  On  the  rear  of  the  same  slide  is  a  special 
holder  C  that  carries  the  threading  tool.  This  consists  of  a 
hob  built  up  of  a  series  of  concentric  disks  provided  with 
cutting  teeth  and  held  on  a  special  arbor  driven  by  a  sep- 


62 


MACHINING  BRITISH   SHELLS 


arate  belt  D.  To  cut  the  thread,  lever  E  is  pulled  down, 
withdrawing  a  stop  which  allows  the  spindle  to  feed  back 
into  the  housing.  The  spindle-driving  mechanism  is  then 
shifted  to  slow  speed,  and  the  spindle  moves  back  at  the 
required  pitch — slightly  over  one  complete  revolution  of  the 
work  (which  takes  forty  seconds)  finishing  the  thread. 
The  work  is  rotated  at  200  R.  P.  M.  for  turning  and  facing, 
and  the  production  is  twenty  per  hour. 


Fig.  36.     Riveting  in  the  Gas  Plug  in  a  "High-Speed"  Hammer 

Final  Machining.  —  The  fourteenth  operation  consists  in 
screwing  in  the  base  plug,  which  is  first  coated  with  red 
lead.  Two  men  are  employed  for  this  operation,  one  in- 
serting the  plug  and  the  other  screwing  it  in  with  a  wrench. 
The  production  is  thirty  per  hour.  The  fifteenth  operation 
consists  in  hogging  off  the  projection  on  the  base  plug  in 


MACHINING  BRITISH   SHELLS 


63 


a  Jenckes  lathe.  First,  a  facing  cut  is  taken  along  the  plug, 
then  the  teat  is  cut  off,  and  finally  a  finishing  cut  is  taken. 
The  production  is  thirty-two  per  hour,  and  the  lathe  is  op- 
erated at  180  R.  P.  M.,  hand  feed  being  used. 

The  sixteenth  operation  consists  in  riveting  in  the  gas 
plug  with  a  "High-Speed"  hammer  operating  at  500  blows 
per  minute,  as  shown  in  Fig.  36.  The  shell  is  held  on  an 


Fig.  37.     Varnishing  Interior  of  High-explosive  Shells 

arbor  and  is  spun  around  by  the  operator  as  the  hammer 
descends.  The  production  is  120  per  hour.  The  seven- 
teenth operation  consists  in  facing  the  base  in  a  Jenckes 
machine,  one  cut  being  taken  at  a  spindle  speed  of  180  R.  P. 
M.  and  1/32  inch  feed  per  revolution  of  the  work.  The 
depth  of  cut  is  3/32  inch.  The  eighteenth  operation  is  cut- 


64 


MACHINING  BRITISH    SHELLS 


ting  the  air  grooves  in  the  waves  in  the  band  groove.  This 
is  accomplished  in  a  Brown-Boggs  inclinable  press  which 
carries  a  fixture  in  which  the  shell  is  located.  The  cuts  are 
made  with  a  punch,  shaped  like  a  cold-chisel,  held  in  the 
ram  of  the  press,  and  the  production  is  240  per  hour.  In 
the  nineteenth  operation,  the  copper  band  is  pressed  into 
the  band  groove  in  a  Goldie  &  McCulloch  hydraulic  press  of 
the  six-cylinder  type.  Three  squeezes  are  required  to  com- 
press this  band,  and  the  production  is  forty  per  hour. 


Fig.  38.     Stamping  in  a  Holden- Morgan   Rotary  Stamping  Machine 

For  the  twentieth  operation,  the  shell  is  brought  back  to 
a  Warner  &  Swasey  brass-working  lathe,  where  the  copper 
band  is  turned  to  shape.  The  work  is  rotated  at  120  R. 
P.  M.  and  roughing  and  finishing  cuts  are  taken.  The 
roughing  cut  is  taken  from  the  front  slide  and  the  finishing 
cut  from  the  rear.  The  shell  is  supported  by  means  of  a 
steadyrest.  The  production  is  forty  per  hour. 


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66  MACHINING  BRITISH   SHELLS 

temperature  for  eight  hours.  The  shells  are  allowed  to  re- 
main in  the  furnace  for  this  time  and  then  are  taken  out 
and  allowed  to  cool  off  in  the  air.  The  twenty-third  opera- 
tion is  cleaning  the  nose  of  the  shell  with  a  rag  and  gasoline. 
The  shells  are  then  ready  for  inspection,  after  which  the 
plug  is  screwed  into  the  nose  end. 

The  twenty-fourth  operation  consists  in  stamping  in  the 
Holden-Morgan  machine  shown  in  Fig.  38.  The  stamp  A 
is  oscillated  by  an  eccentric  and  crank  movement,  and  when 


Fig.  39.     Turning  Long  Bars  from  which  Billets  for  High-explosive 
Shells  are  subsequently  cut 

the  stamp  is  brought  down  in  contact  with  the  work  by 
operating  handwheel  B  the  shell  is  rotated  by  it.  The  pro- 
duction in  this  operation  is  sixty  per  hour.  The  twenty- 
fifth  operation  is  the  final  manufacturing  and  government 
inspection ;  240  completed  shells  represent  eight  hours'  work 
in  this  plant. 

Alternative  Method  of  Machining  British  18-pound  Shells. 
—  A  method  that  is  not  as  widely  practiced  as  that 
just  described  is  outlined  in  Table  II.  By  it,  hot-drawn 


MACHINING  BRITISH    SHELLS  67 

steel  bars  3!/2  inches  in  diameter  by  16  feet  in  length  are 
centered  in  both  ends,  by  first  scribing  two  diametral  lines 
across  the  ends  of  the  bar  and  then  drilling  the  center  holes 
with  a  portable  drill.  The  bars  are  next  set  up  on  centers 
on  an  engine  lathe  and  straightened  with  a  jack  until  they 
run  fairly  true.  One  end  of  the  bar  is  then  stepped  down 
to  the  required  diameter  for  a  length  of  approximately  18 
inches;  the  purpose  of  this  is  to  form  a  bearing  for  the 
steadyrest,  which  is  used  during  the  turning  operation, 
and  also  to  provide  a  starting  point  for  the  special  turning 
head  employed.  The  bars  are  turned  down  to  a  diameter 


Fig.  40.     Cutting  Turned   Bars  to  Shell   Lengths  in  a  Newton 
Cold   Sawing    Machine 

of  3.285  inches  ±  0.005  inch,  and  for  this  purpose  a  special 
traveling  head,  as  shown  in  Fig.  39,  is  employed.  This 
head  carries  five  tools,  three  next  to  the  chuck  and  two  on 
the  opposite  side  of  the  supporting  bushing.  The  first  two 
cutters  are  progressive  roughing  cutters,  the  third  is  a 
"smoothing"  cutter,  and  the  two  cutters  on  the  right-hand 
side  of  the  supporting  bushing  take  finishing  cuts ;  the  depth 
of  the  cut  taken  by  the  last  finishing  tool  is  very  light.  Ac- 
curacy for  diameter  is  determined  by  a  snap  gage  and  a  ring 
gage;  the  snap  gage  is  used  to  make  sure  that  the  bar  is 
not  turned  under  size,  whereas  the  ring  gage  follows  along 


68 


MACHINING  BRITISH    SHELLS 


Fig.  41. 


Machining  Hole  and  Nose  of  Shell   Blank  in   Barnes 
Drilling  Machine 


the  bar  after  the  turning  head.  Should  it  happen  that  the 
last  tool  is  cutting  too  large,  the  operator  takes  a  file  and 
touches  the  high  spots  until  the  ring  gage  will  pass. 

Sawing  Turned  Bars  to  Billet  Lengths. —  Two     Newton 


MACHINING  BRITISH    SHELLS  69 

machines  equipped  with  Huther  inserted-tooth  saw  blades 
are  used  for  cutting  up  the  turned  bars  into  shell  blanks 
9%  inches  in  length.  These  machines,  as  shown  in  Fig.  40, 
hold  four  bars  at  a  time,  and  are  equipped  with  traversing 
work-holding  fixtures  that  move  the  stock  along  after  each 
successive  cut  has  been  completed,  a  stop  being  employed 
to  control  the  length  of  the  blanks.  The  work  is  held  in 
the  fixture  by  a  special  arrangement  of  clamps,  which  are 


Fig.  42.     Close  View  of   Fixture  shown   in   Fig.  41,   illustrating 
Method  of  applying  Tools  to  Work  in  an  Inverted  Position 

operated  by  compressed-air  cylinders  working  in  conjunc- 
tion with  toggle-joints.  In  order  to  facilitate  loading  the 
bars  into  the  work-holding  fixture,  an  auxiliary  rack  is  pro- 
vided in  which  four  bars  are  placed  before  the  four  bars  in 
the  work-h<flding  fixture  have  been  completely  cut.  When 
the  final  blanks  have  been  cut  from  the  bars,  the  work- 
holding  fixture  is  moved  back  to  the  starting  point  and  the 


70  MACHINING  BRITISH   SHELLS 

auxiliary  rack — which  is  pivoted  to  the  base  that  supports 
the  traveling  work-holding  fixture — is  swung  up  by  means 
of  a  crane  hoist.  This  brings  the  next  four  bars  into  posi- 
tion in  the  rack  ready  to  be  clamped. 

The  design  of  the  traveling  work-holding  fixture  is  such 
that  the  bars  cannot  be  completely  cut  up  into  blanks,  the 
crop  end  of  each  bar  having  sufficient  material  for  three 
shell  blanks.  These  crop  ends  are  cut  up  on  another  cold 
saw;  one  of  the  blanks  produced  in  this  way  is  already 
turned  to  size,  while  the  other  two  blanks  are  cut  from  the 
rough  end  of  the  bar  which  was  not  reached  by  the  special 
turning  head  shown  in  Fig.  39.  These  two  rough  crop  ends 
are  turned  down  to  the  required  diameter  on  an  engine  lathe. 

Drilling,  Reaming,  and  Turning  Nose.  —  The  method  used 
for  drilling,  reaming,  and  forming  the  nose  of  the  shell  differs 
greatly  from  that  just  described.  The  development  of  fixtures 
for  performing  this  work  on  the  upright  drilling  machine 
is  unusual,  so  this  method  has  largely  overcome  the  great 
difficulty  experienced  in  securing  early  deliveries  on  all 
forms  of  lathes  for  machining  shells.  Besides,  by  the  in- 
verted-tool method,  chip  trouble  is  largely  overcome.  The 
equipment  used  consists  of  a  battery  of  eight,  self -oiling,  22- 
inch,  all-geared,  drilling  and  tapping  machines  built  by  the 
Barnes  Drill  Co.,  and  much  of  the  credit  for  the  development 
of  this  method  of  machining  shells  is  due  to  the  designers 
employed  by  this  concern.  Figs.  41  and  42  show  one  of 
these  machines  equipped  for  shell  work.  These  show  that 
the  shell  to  be  machined  is  held  by  a  chuck  on  the  drill  spin- 
dle, whereas,  the  tools  that  perform  the  drilling,  reaming  and 
nose-forming  operations  are  carried  by  a  rotary  fixture  B 
supported  on  the  table  of  the  machine.  The  fixture  consists 
of  a  baseplate  and  rotating  table  upon  which  the  tool- 
holders  are  mounted.  The  proper  indexing  of  the  various 
tools  is  provided  for  by  means  of  a  taper  pin  in  the  base  of 
the  fixture  engaging  corresponding  holes  in  the  rotating  ta- 
ble which  is  rigidly  retained  by  a  clamp.  The  sequence  of 
operations  is  as  follows : 

First  Operation: — Spot-drill  and  rough-form  nose  with 
tools  held  in  holder  C.  For  this  operation  the  spindle  ro- 


MACHINING  BRITISH    SHELLS  71 

tates  at  92  R.  P.  M.  with  a  down  feed  of  0.013  inch  per 
revolution.  The  drilling  is  done  by  a  short  twist  drill,  and 
the  rough-forming  of  the  nose  by  three  turning  tools  which 
are  stepped  in  so  that  they  cut  to  different  depths,  leaving 
an  irregular  surface  that  is  finished  in  a  subsequent  opera- 
tion. The  shell  is  supported  by  a  bronze-lined  bushing 
so  that  the  work  is  adequately  supported  while  being 
machined. 

Second  Operation: — Drill  hole  in  shell  to  required  depth 
with  a  drill  D  1 13/16  inch  in  diameter.  For  this  opera- 
tion the  spindle  is  rotated  at  145  R.  P.  M.  and  at  a  feed  of 
0.013  inch  per  revolution. 

Third  Operation: — Rough-ream  the  hole  with  reamer  E, 
which  is  formed  at  the  end  to  finish  the  bottom  of  the  cavity 
to  the  required  shape.  For  reaming,  the  spindle  is  oper- 
ated at  37  R.  P.  M.  with  a  down  feed  of  0.093  inch  per 
revolution.  When  the  reamer  reaches  the  pointed  end  of 
the  hole  as  left  by  the  twist  drill,  the  power  feed  is  disen- 
gaged and  the  spindle  fed  down  by  hand  until  the  positive 
stop  is  reached. 

Fourth  Operation: — Finish-form  nose  with  form-cutter 
located  in  holder  F,  which  is  bronze-lined.  The  spindle  is 
rotated  at  45  R.  P.  M.  and  fed  down  by  hand. 

Fifth  Operation: — Cut  step  and  bevel  on  nose  of  shell. 
The  work  is  supported  by  a  bronze-lined  tool-holder  G,  and 
the  machine  is  operated  at  the  same  speed  and  feed  as  for 
the  fourth  operation.  The  bevel  on  the  inside  of  the  nose 
is  machined  by  a  double-ended  cutter  of  the  proper  form, 
which  is  supported  at  the  center  by  a  toolpost  bolted  to  the 
base  of  the  fixture.  The  step  is  formed  by  two  forming 
tools  carried  by  toolposts  bolted  to  the  base  of  the  fixture. 

Sixth  Operation: — Finish-ream  with  reamer  H.  This 
operation  must  be  performed  with  great  care,  as  the  speci- 
fications require  that  when  an  electric  light  is  dropped  into 
the  hole,  the  surface  will  show  a  uniform  polish  in  all  places. 
This  operation  is  performed  with  the  spindle  rotating  at 
37  R.  P.  M.  with  a  down  feed  of  0.093  inch  per  revolution. 

By  holding  the  shell  in  a  fixture  on  the  drill  spindle,  ad- 
vantage is  taken  of  the  inverted  principle  which  allows  the 


72  MACHINING  BRITISH    SHELLS 

chips  to  clear  themselves  more  freely  than  would  otherwise 
be  the  case.  All  the  drilling  and  reaming  tools  used  are  of 
the  oil-tube  type  and  are  supplied  with  forced  lubrication. 
The  chuck  in  which  the  work  is  held  is  arranged  with  three 
serrated  eccentric  jaws  mounted  on  a  rotating  ring.  To 


Fig.  43.     Drilling  and  tapping  Hole  for  Fuse  Fixing  Screw 

clamp  the  work  in  the  chuck,  the  ring  that  carries  the  jaws 
is  turned  back  against  spring  tension  to  allow  the  work 
to  be  pushed  up  into  place.  The  ring  is  then  released  and 
snaps  back  to  give  the  jaws  a  preliminary  grip  on  the  shell. 
When  the  machining  operation  is  commenced,  the  resistance 
of  the  work  to  the  cutting  action  of  the  tools  causes  a  fur- 


MACHINING  BRITISH   SHELLS  73 

ther  rotation  of  the  ring  on  which  the  chuck  jaws  are  car- 
ried, with  the  result  that  the  jaws  rock  in  on  their  eccen- 
tric pivots  to  secure  a  firmer  grip  on  the  work.  After  the 
machining  operations  have  been  completed,  the  work  is  re- 
moved from  the  chuck  by  a  wrench  which  is  slipped  over  the 
end  of  one  of  the  jaws,  and  pressure  is  applied  to  rotate  the 
chuck  ring  in  the  opposite  direction  from  that  necessary  to 
tighten  the  jaws. 

Drilling  and  Tapping  for  Fixing  Screw. — The  operation 
of  drilling  and  tapping  the  hole  in  the  nose  for  the  fuse 
fixing  screw  is  accomplished  in  a  two-spindle  drilling  ma- 


Fig.  44.     Milling  Threads  in  Nose  In  a  Special   Lees-Bradner  Thread   Milling 

Machine 

chine  as  shown  in  Fig.  43.  The  first  spindle  is  used  for 
counterboring  and  drilling.  After  the  hole  has  been  started 
with  drill  A,  it  is  removed  and  the  smaller  drill  B  inserted. 
The  fixture  carrying  the  work  is  now  moved  over  to  the 
second  spindle  of  the  machine  and  the  hole  threaded  with 
tap  C,  which  is  held  in  an  Errington  chuck.  For  this  oper- 
ation, of  course,  it  is  necessary  to  remove  the  drill  guide 
bushing. 

Milling  Threads  in  Nose.  —  In  the  special  Lees-Bradner 
thread  milling  machine  shown  in  Fig.  44,  the  shell  is  held 
in  an  air  chuck  with  the  open  end  out.  The  threading  is 
done  with  a  multiple  type  cutter  A,  of  a  length  sufficient 


74  MACHINING  BRITISH    SHELLS 

to  completely  cover  the  length  of  the  part  to  be  threaded 
and  which  is  rotated  by  a  separate  belt  B.  The  cutter-slide 
is  fed  toward  the  head  of  the  machine,  and  the  work  ro- 
tated at  the  same  time  so  as  to  cut  a  thread  of  the  correct 
pitch.  This  is  controlled  through  a  change-gear  system  lo- 
cated at  the  left-hand  end  of  the  machine. 

Turning,  Under-cutting,  and  Waving  Band  Groove.  — 
Before  the  machining  of  the  band  groove,  a  center  hole  is 
drilled  in  the  base  end  of  the  shell.  After  this  operation, 
the  shells  go  to  the  preliminary  inspection  department 


Fig.  45.     Turning,  under-cutting  and  waving   Rifling  Band  Groove 

where  the  thread  in  the  nose  is  tested  with  a  thread  plug 
gage.  A  driving  center  is  then  screwed  into  the  nose  of 
the  shells,  and  they  are  returned  to  the  machining  depart- 
ment. The  band  groove  is  machined  as  shown  in  Fig.  45. 
The  roughing  out  of  the  band  groove  is  done  by  means  of  a 
formed  tool  held  on  the  rear  cross-slide,  which  leaves  suffi- 
cient stock  to  form  the  waves.  The  next  step  is  to  under-cut 
the  sides  of  the  band  groove  by  two  tools  held  in  the  holder 
B;  when  one  tool  is  in  action,  the  other  clears  the  end  of  the 
shell.  The  machining  of  the  waves  is  performed  by  a  tool  C 
held  in  the  holder  D.  This  holder  forms  part  of  a  slide 


MACHINING  BRITISH    SHELLS 


75 


which  carries  a  roller  that  engages  with  cam  E.  Spring  F 
keeps  the  roll  in  contact  with  the  cam,  so  that,  when  the  lat- 
ter rotates,  an  oscillating  movement  is  imparted  to  holder  D. 
Preliminary  Inspection.  —  After  the  band  seats  have  been 
machined,  the  driving  centers  are  removed  from  the  nose 
of  the  shells  and  the  latter  are  subjected  to  a  preliminary 
inspection.  This  consists  in  weighing  in  order  to  determine 
the  amount  of  stock  that  must  be  removed  from  the  base  to 
bring  the  shells  to  standard  weight.  The  normal  weight  of 
the  finished  shell  is  14  pounds,  13.15  ounces,  and  a  tolerance 


Fig.  46.     Facing-off   Base   End  and   machining   Gas  Plug   Seat 

of  1  ounce  is  allowed.  Experiments  have  established  the 
fact  that  each  ounce  of  weight  on  the  shell  is  equivalent  to 
0.026  inch  in  length  at  the  base,  so  that,  by  removing  the 
metal  on  this  basis,  the  weight  of  the  shell  may  be  reduced 
to  normal.  The  inspector  who  weighs  the  shells  has  a  chart 
before  him  on  which  the  various  weights  of  shells  are  type- 
written, together  with  the  corresponding  amount  of  metal, 
in  thousandths  of  an  inch,  that  must  be  removed  from  the 
base  in  order  to  bring  the  shell  to  normal  weight.  At  this 
stage,  the  shells  also  have  the  heat  number  of  the  steel  bar 
stamped  on  the  base;  as  the  metal  is  to  be  removed  from 


76  MACHINING  BRITISH   SHELLS 

the  base,  the  inspector  transfers  this  heat  number  to  the 
side  of  the  shell.  After  he  has  weighed  the  shell  and  de- 
termined the  amount  of  metal  that  must  be  removed,  he 
marks  the  number  of  thousandths  inch  to  be  removed  on  the 
side  of  the  shell  with  blue  chalk ;  the  shells  are  then  sent  on 
to  the  lathe  department  where  the  correction  for  weight  is 
made  while  the  hole  is  being  bored  to  receive  the  gas  plug. 


Fig.  47.     Fixture  used  for  driving  in  Gas  Plugs 

Facing  Base  End  of  Shell. —  The  engine  lathe  used  for 
facing  the  base  end  is  equipped  with  a  special  micrometer 
attachment  which  enables  quick  settings  to  be  made.  This 
attachment,  as  shown  in  Fig.  46,  consists  of  a  bracket 
bolted  to  the  lathe  bed,  on  which  the  spindle  of  a  micrometer 
A  is  supported.  The  connection  between  the  micrometer 
and  the  supporting  bracket  is  cushioned  by  a  spring,  so 
that,  when  the  lathe  carriage  is  brought  up  against  the  mi- 


MACHINING  BRITISH   SHELLS  77 

crometer  spindle,  the  spring  will  take  up  the  strain  and  pre- 
vent the  instrument  from  being  damaged. 

In  operation,  the  shell  is  gripped  in  a  Hannifin  air  chuck 
and  the  facing  tool  brought  into  contact  with  the  base  of  the 
shell.  The  micrometer  spindle  is  then  screwed  up  against 
the  end  of  the  lathe  carriage  and  a  reading  taken,  after 
which  the  spindle  is  backed  away  the  necessary  number  of 
thousandths  inch  that  the  inspector  has  found  must  be  re- 
moved from  the  shell  to  bring  it  to  normal  weight.  The 
carriage  is  moved  out  until  the  tool  clears  the  work,  then 
moved  to  the  left  until  it  makes  contact  with  the  micrometer 
spindle.  After  this  setting,  the  cross-slide  is  fed  in  until 
the  tool  passes  beyond  the  circumference  of  the  hole  subse- 
quently to  be  bored.  The  cross-slide  is  then  backed  away 
from  the  work  and  the  boring  tool  B  held  in  the  tailstock 
spindle  is  fed  in  to  bore  the  hole  for  the  plug.  The  turret 
toolpost  is  then  revolved  to  bring  the  reaming  tool  into 
position  to  take  a  finish  cut  on  the  side  and  bottom  of  the 
hole.  The  tool  used  for  this  purpose  has  a  double  cutting 
edge  with  the  edges  located  at  right  angles  to  each  other. 
After  the  finish  cut  has  been  taken,  the  turret  toolpost  is 
again  rotated  to  bring  the  under-cutting  tool  into  the  work- 
ing position,  and  the  under-cut  is  made. 

Gas  Plugs.  —  The  shells  now  go  to  another  Lees-Bradner 
thread  milling  machine  of  the  type  shown  in  Fig.  44,  where 
the  threads  for  the  gas  plugs  are  milled.  These  plugs  are 
drop-forgings  provided  with  a  triangular  head  to  fit  the 
wrench  used  in  screwing  them  into  the  shells.  Before  being 
screwed  into  place,  the  disks  are  painted  with  red  lead  on 
the  bottom  and  threads  and  screwed  loosely  into  the  shells. 
The  work  then  goes  to  an  upright  drilling  machine,  Fig.  47, 
equipped  with  a  special  fixture  for  use  in  driving  the  gas 
plugs  down  firmly  into  the  shells.  The  machine  spindle  car- 
ries a  heavy  flywheel  A  to  give  the  necessary  momentum. 
The  fixture  B  in  which  the  work  is  held  is  pivoted  on  the 
table  of  the  drilling  machine  so  that  it  may  be  swung  out 
of  the  way  of  the  flywheel  for  setting  up  the  work  and  re- 
moving the  shell  after  the  plug  has  been  driven  home,  a  stop 
being  provided  for  locating  the  work  under  the  spindle. 


78  MACHINING  BRITISH    SHELLS 

The  end  of  the  spindle  is  fitted  with  a  wrench  which  en- 
gages the  triangular  nut  on  the  disk  when  the  spindle  is  fed 
down.  When  engagement  is  made  in  this  way,  the  momen- 
tum of  the  flywheel  drives  the  disk  home  with  sufficient 
force  to  screw  it  firmly  into  place,  after  which  the  continued 
motion  of  the  spindle  results  in  twisting  the  corners  off  the 
nut. 

It  is  now  necessary  to  remove  the  projection  from  the 
base  of  the  gas  plug,  and  face  off  the  base  of  the  plug.  For 
this  purpose  the  shells  are  taken  to  an  engine  lathe  equipped 
with  a  Hannifin  air  chuck  and  a  turret  toolpost.  The  pro- 
jection is  removed  by  a  roughing  tool,  after  which  the  tur- 
ret head  is  revolved  to  bring  a  finishing  tool  into  position  to 
take  a  light  cut  across  the  entire  base  of  the  shell.  The  tur- 
ret head  is  again  rotated  to  bring  a  third  tool  carrying  a 
hardened  tool-steel  roller  into  position.  This  roller  is  used 
to  spin  over  the  slight  seam  between  the  plug  and  cavity 
in  the  shell.  The  result  is  that  any  slight  burr  which  was 
raised  at  the  joint  during  the  turning  operation  is  rolled 
down,  making  the  joint  so  smooth  that  it  can  hardly  be  seen. 

Pressing  and  Forming  the  Copper  Band. — The  shells 
now  go  to  a  West  Tire  Setter  Co.  banding  press,  where  the 
copper  band  is  pressed  into  the  groove.  After  this  has  been 
done,  the  shells  are  passed  on  to  an  engine  lathe  equipped 
with  a  Hannifin  air  chuck  and  formed  tools  for  forming 
the  bands.  Two  forming  tools  are  used  for  this  purpose, 
the  roughing  tool  being  a  radial  tool  carried  at  the  front  of 
the  fixture  bolted  to  the  cross-slide,  whereas,  the  finishing 
tool  is  of  the  tangential  type  and  is  located  at  the  back  of  the 
fixture.  The  shells  are  then  taken  to  a  Dwight  Slate  stamp- 
ing machine,  where  they  are  marked.  They  are  then 
washed  in  hot  soda  water  to  remove  the  grease,  after  which 
they  are  washed  in  alcohol  to  remove  all  traces  of  soda.  As 
the  shells  come  from  the  alcohol  bath,  they  are  taken  out 
and  placed  on  an  inclined  table,  on  which  they  roll 
down  until  they  come  into  contact  with  an  accumulation  of 
shells  at  the  base.  These  shells  are  in  a  convenient  position 
for  the  man  who  performs  the  painting  operation  on  the  in- 
side. The  device  used  for  this  purpose  consists  of  two  rol- 


MACHINING  BRITISH    SHELLS  79 

lers,  which  are  normally  located  beneath  the  surface  of  the 
bench.  When  the  operator  is  ready  to  paint  a  shell,  he 
takes  it  from  the  bench  and  places  it  in  position  over  the 
hole  through  which  the  rollers  are  raised  by  depressing  a 
foot-treadle.  The  result  is  that  the  shell  is  held  between 
two  rollers  which  impart  a  rotary  motion  to  it.  The 
painter  then  takes  a  round  brush  of  suitable  size,  dips  it 
into  the  shellac  pot  and  pushes  it  into  the  shell.  An  ex- 
perienced painter  can  varnish  shells  very  rapidly  by  this 
method. 

After  the  varnish  in  the  shells  has  dried,  they  are  in- 
spected; the  production  is  1000  per  day  of  twenty-three 
hours.  Eight  shells  from  each  day's  production  are  sent  to 
the  proving  grounds  for  test,  and  as  soon  as  a  favorable 
report  has  been  obtained,  the  shells  are  shipped  to  the  load- 
ing factory. 


CHAPTER  V 
MACHINING  RUSSIAN  AND  SERBIAN  SHELLS 

FOLLOWING  the  forging  of  the  Russian  3-inch  high-explo- 
sive shell,  Fig.  48,  the  first  machining  operation  is  cutting 
off  the  open  end.  This  is  done  in  a  Curtis  &  Curtis  shell 
cutting-off  machine,  as  shown  in  Fig.  49.  The  forging  is 
located  by  means  of  the  gage  shown  at  the  front  of  the  ma- 
chine, and  the  cutter  head,  carrying  four  radial  cutters,  is 
rotated  about  the  stationary  shell.  The  cutters  are  auto- 


Machinery 


Fig.  48.     Russian  3-inch  High-explosive  Shell  and  Plug 

matically  fed  into  the  work  and  at  the  end  of  the  cut  are 
returned  to  the  starting  point.  The  cutting  is  done  at  a 
work  speed  of  65  surface  feet  per  minute,  and  a  lubricant 
called  "Cut-cool"  is  used  for  cooling  and  lubricating  the 
work.  The  wall  of  the  shell  is  about  1/2  incn  thick,  and 
the  cutting  off  is  done  at  the  rate  of  fifty  shells  per  hour. 
On  an  average,  100  shells  are  cut  off  before  the  cutters 

80 


MACHINING  RUSSIAN   SHELLS 


81 


require  grinding.  The  base  end  is  now  centered  in  a  Rock- 
ford  drilling  machine  provided  with  a  special  arbor  mounted 
on  the  table  over  which  the  shell  is  slipped.  After  being 
centrally  located,  the  shell  is  drilled  and  countersunk  with 
a  combination  center  reamer. 

Heat-treating  Russian  High-explosive  Shells. —  It  is  the 
practice  of  one  plant  to  heat-treat  the  Russian  high-explo- 


Fig.  49.     Cutting  off  Open   End  of  Shell   Forging 

sive  shell  before  any  of  the  important  machining  operations 
are  performed ;  in  fact,  it  is  heat-treated  after  the  centering 
operation  just  described.  Fig.  50  shows  the  furnace  used 
for  heating  the  shell  previous  to  quenching ;  this  is  designed 
and  built  by  the  Laconia  Car  Co.,  and  is  shown  in  detail  in 
Fig.  22.  The  shells  are  loaded  into  the  furnace  seven  at  a 


82  MACHINING  RUSSIAN   SHELLS 

time  by  a  special  fork  mounted  on  wheels,  as  shown  in  Fig. 
50.  The  furnace  holds  thirty-five  shells,  and  it  requires 
thirty-five  minutes  to  heat  one  lot  of  shells  to  the  desired 
temperature — 1470  degrees  F.  (about  800  degrees  C.).  In 
removing  the  shells  from  the  furnace,  the  fork  is  rolled 
under  a  layer  of  seven  shells,  which  are  pulled  out,  the 
shells  are  gripped  by  a  pair  of  tongs,  and  quickly  immersed 
in  a  bath  of  running  water.  They  are  placed  on  racks  at 


Fig.    50.     Heating    Russian    High-explosive    Shell    Forgings   for 
Hardening 

the  bottom  of  the  bath  and  allowed  to  get  thoroughly  cool 
before  removing. 

The  tempering  is  done  in  lead  baths,  also  designed  and 
built  by  the  Laconia  Car  Co.,  which  are  34  inches  wide,  34 
inches  high,  and  4  feet  9  inches  long.  The  lead  pot  proper 
is  of  cast  iron  with  one-inch  walls,  and  measures  12 1/£  by 
14  by  24%  inches.  It  is  surrounded  by  a  1%-inch  firebrick 
lining.  One  burner  is  used  to  heat  the  lead  bath  to  1100 


MACHINING  RUSSIAN   SHELLS  83 

degrees  F.  (about  600  degrees  C.)  ;  this  burner  consumes 
41/2  gallons  of  fuel  oil  per  hour.  The  shells  are  completely 
submerged  in  the  bath  for  seven  minutes,  then  taken  out 
and  allowed  to  cool  slowly  in  the  sand.  To  keep  the  shells 
below  the  surface  of  the  lead  bath,  they  are  suspended  on 
pins  held  on  a  crank,  which  is  turned  to  force  the  shells 
down  or  bring  them  up  as  required.  Five  men,  with  the  aid 
of  three  muffle  furnaces  and  two  lead  pots,  can  heat-treat 
100  shells  per  hour. 

Rough-turning  External  Diameter.    — Following      heat- 
treating,  the  shells  are  rough-turned  in  a  16-inch  lathe,  as 


Fig.  51.     Rough-turning  External   Diameter 

shown  in  Fig.  51.  The  shell  A  is  supported  at  the  closed 
end  on  the  lathe  center,  and  is  supported  and  driven  from 
the  open  end  on  the  taper  mandrel  B.  This  resembles  a 
reamer  in  shape,  but  is  not  provided  with  cutting  edges. 
A  single  cutting  tool  is  used  and  the  depth  of  the 
cut  varies  from  3/16  to  %  inch  on  the  diameter.  The  work 
is  rotated  at  a  surface  speed  of  from  60  to  70  feet  per  min- 
ute, and  the  feed  is  1/16  inch  per  revolution. 

Machining  Interior  of  Russian  High-explosive  Shell.  — 
The  boring,  counterboring,  and  reaming  operations  on  the 
interior  of  the  Russian  high-explosive  shell  are  performed  on 
a  turret  lathe,  as  shown  in  Fig.  52.  The  order  of  opera- 


84  MACHINING  RUSSIAN   SHELLS 

tions  is  as  follows :  First,  bore  mouth  of  shell  with  boring 
tool  A;  second,  rough-drill  entire  length  of  shell  with  tool 
B;  third,  finish-drill  with  tool  C;  fourth,  finish  bottom  of 
shell  with  tool  D;  fifth,  finish-ream  entire  length  of  shell 
with  tool  E;  and  sixth,  counterbore  with  tool  F. 

Following  the  operations  on  the  inside,  the  shell  is  held 
in  a  three-jaw  chuck  on  a  Davis  lathe,  and  the  solid  end  is 
rough-faced.  After  this,  the  shell  is  again  chucked  and  the 
mouth  is  recessed  preparatory  to  threading.  Following 
this,  the  shell  is  held  in  a  four- jaw  chuck,  as  shown  in  Fig. 


Fig.  52.     Boring,  counterborlng  and  reaming  Cavity  of  Russian 
High-explosive  Shell 

53,  the  outer  end  being  supported  by  a  steadyrest.  The 
operations  performed  at  this  setting  consist  in  roughing  out 
the  thread  with  tool  A,  taking  a  light  cut  across  the  end  with 
tool  B,  and  finishing  the  thread  with  tap  C. 

Final  Turning,  Facing,  and  Banding  Operations.  —  The 
base  end  of  the  shell  is  now  finish-faced,  the  corners  rounded 
slightly,  and  the  band  groove  cut.  The  next  step  is  to  ma- 
chine the  under-cut  in  the  band  groove,  which  is  performed 
by  means  of  a  special  fixture.  After  this,  the  adapter  or 


MACHINING  RUSSIAN   SHELLS  85 

nose  is  fitted  into  the  end  of  the  shell,  and  the  end  of  the 
shell  is  machined  to  shape.     This  operation  is  performed  by 


Fig.  53.     Facing   and  threading   Nose  of   High-explosive   Shell 


Fig.  54.     Turning   Radius  on   Nose  of  Shell 

inserting  a  nose  plug  that  is  used  as  a  center,  as  shown  in 
Fig.  54.    The  radius  turning  is  done  by  means  of  a  former- 


86  MACHINING  RUSSIAN   SHELLS 

plate  A,  against  which  the  roll  B  held  on  the  carriage  is 
pulled  by  a  heavy  weight  attached  to  chain  C.  Grinding  of 
the  body  of  the  shell  is  now  performed  on  a  plain  grinding 
machine,  in  which  the  three-operation  method  is  employed. 
This  is  followed  by  pressing  on  the  band,  which  is  done  in  a 
West  Tire  Setter  Co.  shell  banding  press.  The  rifling  band 
is  now  formed  to  the  required  shape  in  a  Jenckes  machine, 
as  shown  in  Fig.  55.  Here,  the  shell  is  held  in  a  three-jaw 
chuck  and  the  band  is  formed  to  shape  by  a  single  forming 
cutter.  Proper  location  of  the  shell  in  the  chuck  is  ob- 
tained by  a  gage  located  within  the  chuck. 


Fig.  55.     Turning  Copper  Band  on  Jenckes  Machine 

Machining  the  Adapter  or  Nose. —  The  nose  or  adapter 
A,  Fig.  48,  for  the  Russian  high-explosive  shell  is  turned 
from  bar  stock  in  a  314-inch  Gridley  automatic  turret  lathe. 
The  first  operation,  after  feeding  the  stock  to  the  stop,  is 
drilling  and  rough-turning  the  outside  and  thread  diameter. 
These  operations  are  performed  from  the  turret  and  the 
work  speed  is  120  R.  P.  M.,  the  feed  of  the  tools  being  0.009 
inch  per  revolution  of  the  work.  The  tools  held  on  the 
second  turret  face  counterbore  and  finish-turn  the  thread 


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MACHINING  SERBIAN   SHELLS 


out  the  center  hole  and  cutting  the  internal  thread ;  this  is 
done  on  a  14-inch  lathe.  The  first  step  is  to  take  a  light 
finishing  cut  from  the  hole,  after  which  it  is  threaded.  The 
production  is  about  four  pieces  per  hour.  The  drilling, 
counterboring,  and  tapping  of  the  hole  for  the  set-screw  B, 
Fig.  48,  comes  next,  and  this  is  performed  on  a  three-spindle 
sensitive  drilling  machine;  the  production  is  twenty  pieces 
per  hour.  The  two  wrench  holes  C  are  then  milled  in  a  hand 
milling  machine,  one  at  a  time ;  the  production  is  sixty  per 
hour. 


0.590 
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-- 


Machinery 


Fig.   56.     Serbian  75-millimeter   High-explosive   Shell 

Machining  Serbian  75-millimeter  Shells.  —  After  the 
forging  has  been  completed,  the  first  machining  operation 
on  the  Serbian  75-millimeter  high-explosive  shell  shown  in 
Fig.  56  is  cutting  off  the  open  and  closed  ends;  the  full 
series  of  operations  is  given  in  Table  III.  The  cutting  of 
the  ends  is  done  on  an  Espen-Lucas  cold  saw,  as  shown  in 
Fig.  57,  at  the  rate  of  160  per  day.  In  this  operation,  in 
addition  to  cutting  off  the  excess  stock  on  the  open  end, 
about  3/16  inch  of  stock  is  removed  from  the  closed  end  of 


MACHINING   SERBIAN   SHELLS  89 

the  forging.  The  illustration  shows  that  three  shells  are 
loaded  in  one  side  of  the  machine  by  the  swinging  arm  car- 
rying the  three  gages  while  the  saw  is  operating  on  the 
three  shells  on  the  other  side. 

Following  this  operation  comes  the  centering,  which  is 
done  on  an  engine  lathe,  as  shown  in  Fig.  58.  The  man- 
drel on  which  the  work  is  held  carries  two  sets  of  three 
fingers  that  are  expanded  by  a  tapered  draw-in  bar  operated 
by  a  handwheel  at  the  rear  of  the  spindle.  A  combination 
drilling  and  centering  tool  is  used,  and  the  production  is  300 
shells  per  day. 


Fig.  57.     Cutting  off  Excess  Stock  from  Open  and  Closed  Ends  of 
Forging 

Turning  and  Boring. —  The  shells  now  go  to  the  turning 
department  where  the  first  operation  is  facing  and  beveling 
the  closed  end.  Reference  to  Fig.  56  will  show  that  the 
Serbian  shell  has  a  pronounced  bevel  at  the  base  end,  and 
this  is  roughed  out  at  this  time  and  the  base  faced,  leaving 
a  teat  about  11/16  inch  in  diameter.  The  facing  and  bevel- 
ing is  done  on  a  21-inch  engine  lathe,  using  two  tools,  one  of 
which  cuts  the  bevel  and  the  other  faces  the  end.  The  cut- 
ting speed  is  65  feet  per  minute ;  the  production  is  from  fifty- 
five  to  sixty  shells  per  day. 

The  next  operation  is  rough-turning,  as  shown  in  Fig.  59. 


90  MACHINING   SERBIAN   SHELLS 

This  is  accomplished  on  a  17-inch  engine  lathe,  at  a  work 
speed  of  44  surface  feet  per  minute.  The  amount  of  metal 
removed  averages  %  inch  on  the  diameter,  and  the  feed  is 
0.024  inch  per  revolution  of  the  work.  This  rough-turning 
operation  leaves  the  shell  about  0.050  inch  larger  than  the 
finished  size.  The  production  is  from  fifty-five  to  sixty 
shells  per  day.  Following  this,  a  semi-finish  cut  is  taken 
from  the  external  diameter  on  a  17-inch  engine  lathe.  For 
this  operation  the  work  speed  is  55  surface  feet  per  minute. 
The  amount  of  metal  removed  is  0.025  inch  on  the  diameter, 


Fig.  58.     Centering  Closed   End  of  Forging 

and  the  feed  is  0.040  inch  per  revolution.     The  production  is 
from  ninety  to  one  hundred  shells  per  day. 

The  machining  operations  on  the  cavity  of  the  shell  are 
performed  on  double-spindle  flat  turret  lathes.  In  the  first 
position,  the  operation  performed  is  rough-boring  with  a  sin- 
gle-point tool,  removing  14  inch  of  stock  from  the  diameter ; 
second,  roughing  out  taper  with  a  flat  boring  tool  and  re- 
cessing mouth  with  another  tool  held  in  the  same  bar ;  third, 
finish-boring  full  length  of  hole  with  a  combination  straight 
and  taper  boring  tool,  also  boring  diameter  to  be  threaded  ; 
(The  boring  tool-holder  used  carries  two  blades,  one  set  at 
right  angles  to  the  other ;  the  first  tool  bores  the  taper  sec- 


MACHINING   SERBIAN   SHELLS  91 

tion  and  part  of  the  straight  section,  whereas,  the  second 
tool  finishes  the  straight  section  only.)  ;  fourth,  tapping 
mouth  end  of  shell.  The  production  is  thirty-four  shells 
per  day. 

A  center  plug  is  now  screwed  into  the  open  end  of  the 
shell  and  it  is  taken  to  the  21-inch  engine  lathe  shown  in 
Fig.  60.  The  lathe  is  provided  with  a  turret  toolpost,  and 
carries  three  cutting  tools  and  a  knurl.  The  first  operation 
is  to  cut  the  groove  with  a  broad-nose  tool ;  second,  cut  two 
concentric  rings  (one  for  crimping  in  cartridge  case)  with 


Fig.  59.     Rough-turning  External  Diameter  of  Shell 

a  forming  tool;  third,  under-cut  base  side  of  band  groove 
0.010  inch  under-cut ;  fourth,  knurl  band  groove.  The  pro- 
duction is  from  ninety  to  one  hundred  shells  per  day.  The 
shell  is  now  taken  to  a  17-inch  engine  lathe,  where  a  light 
cut  is  taken  from  the  external  diameter,  leaving  it  0.015 
inch  over  size.  The  turning  commences  at  the  rifling  band 
groove  and  terminates  at  a  point  about  two  inches  from  the 
nose.  The  production  is  from  100  to  110  shells  per  day. 

Finishing  the   Machining. —  Following  this   is   the   final 
finishing,  which  is  accomplished  in  a  17-inch  engine  lathe. 


92  MACHINING   SERBIAN   SHELLS 

Two  tools  are  used  for  this  operation ;  one  is  set  to  the  fin- 
ished size  of  the  shell  at  the  base  end  back  of  the  band 
groove,  and  the  other  is  set  for  the  reduced  size.  The  pur- 
pose of  this  reduction  is  to  allow  clearance  for  the  shell  in 
passing  through  the  gun.  The  production  is  120  shells  per 
day.  The  projection  on  the  base  end  of  the  shell  is  now  re- 
moved on  a  band  saw.  This  is  done  at  the  rate  of  two  shells 
per  minute.  After  sawing  off  the  center  projection,  the 
base  end  is  squared  up  on  a  17-inch  engine  lathe.  The  tur- 
ret toolpost  carries  two  tools ;  one  of  these  faces  the  end  a'nd 
the  other  trues  up  the  bevel.  The  production  is  from  110  to 
120  per  day.  Before  any  other  operations  are  performed  on 
the  shell,  the  ogive  is  assembled. 


Fig.  60.     Turning  and  Knurling  Band  Groove 

Machining  Ogive  for  Serbian  Shell. —  The  ogive  that  fits 
in  the  nose  of  the  Serbian  75-millimeter  high-explosive  shell 
is  turned  out  from  bar  stock  containing  about  50  points 
carbon.  The  first  operation  is  performed  on  a  41/4-inch 
Gridley  single-spindle  automatic.  The  bar  is  fed  to  the 
stop  located  on  a  "corner"  of  the  turret  slide ;  the  operations 
are :  First,  drill  the  small  hole,  and,  at  the  same  time,  take  a 
light  cut  from  external  diameter  and  face  end  of  work; 
second,  bore  hole  from  turret,  also  chamfer  inside  with  a 
hook  tool;  third,  neck  at  base  of  thread  with  a  regular 
Gridley  internal  necking  tool,  and,  at  the  same  time,  form 


MACHINING   SERBIAN   SHELLS 


93 


outside  diameter  to  full  width  with  a  forming  tool  carried 
on  the  cross-slide ;  fourth,  cut  off.  For  centering,  boring, 
and  facing,  the  stock  revolves  at  140  R.  P.  M.  and  the  feed 
is  0.010  inch  per  revolution.  For  forming,  the  speed  is 
slowed  down  to  80  R.  P.  M.  and  the  feed  to  0.008  inch  per 
revolution.  The  cutting  off  is  done  at  a  spindle  speed  of 
140  R.  P.  M.  with  a  tool  feed  of  0.012  inch.  Production  is 
eight  per  hour. 

The  cutting  of  the  internal  thread  is  done  on  an  "Automa- 
tic" threading  lathe, 

using  a  circular  tool 
on  the  bar.  The  spin- 
dle of  the  machine  ro- 
tates at  72  R.  P.  M. 
and  it  takes  from 
fifteen  to  twenty 
passes  of  the  tool  to 
complete  the  thread. 
The  production  aver- 
ages six  pieces  per 
hour.  The  thread  on 
the  external  diameter 
is  cut  on  a  turret  lathe, 
where  the  work  is  held 
on  an  expanding 
threaded-stud  m  a  n  - 
drel.  The  operations 
are :  First,  face  the 

Seat  On  the  Under  Side  Fig-  61>     Assembling  Ogive  In  Shell  Nose 

of  the  ogive  that  comes  in  contact  with  the  front  end  of  the 
shell;  second,  thread  external  diameter;  third,  chamfer 
thread  and  burr  hole.  The  facing  and  burring  operations 
are  accomplished  at  a  spindle  speed  of  60  R.  P.  M.,  whereas, 
for  threading,  the  speed  is  cut  down  to  24  R.  P.  M. 

Setting  in  the  Ogive.  —  After  the  ogive  has  been  com- 
pletely machined,  it  is  assembled  in  the  nose  of  the  shell, 
which  is  done  on  a  drilling  machine,  as  shown  in  Fig.  61. 
The  shell  is  gripped  in  a  hinged  fixture  fastened  to  the  table 
of  the  drilling  machine  and  a  special  tool  similar  in  shape 


94  MACHINING   SERBIAN   SHELLS 

to  an  inverted  cone,  the  inside  surface  of  which  is  serrated, 
is  used  to  assemble  the  ogive  in  the  shell.  The  ogive  is 
started  into  the  shell  by  hand  and  then  the  tool  is  brought 
down  in  contact  with  it,  driving  it  down  to  the  seat. 

The  shell  is  now  taken  to  a  17-inch  engine  lathe  where 
the  radius  is  turned,  as  shown  in  Fig.  62.  Here  it  is 
gripped  in  a  collet  chuck,  being  located  centrally  in  this 
chuck  by  means  of  a  special  gage  located  on  the  tailstock 
spindle.  After  clamping,  the  turning  tool  A  is  brought  in 
contact  with  the  work  and  is  guided  in  its  operation  by 


Fig.   62.     Turning   Ogive   in   Open    End   of  Shell 

means  of  a  former-plate  B  fastened  to  a  fixture  held  to  the 
bed  of  the  lathe.  The  movement  of  the  cross-slide  is  con- 
trolled by  a  roller  C  that  makes  contact  with  this  former- 
plate,  the  latter  being  kept  in  contact  with  the  plate  by 
means  of  two  ropes  to  which  weights  are  attached  and 
which  run  over  pulleys,  as  illustrated.  The  production  is 
seventy  per  day. 

Following  the  turning  of  the  nose,  the  copper  band  is 
now  pressed  into  the  groove  in  a  West  Tire  Setter  Co.'s 
banding  press.  The  bands  are  annealed  before  being 


MACHINING  SERBIAN   SHELLS  95 

pressed  on  the  shell  and  two  squeezes  are  necessary  to  com- 
press the  band  into  the  groove.  The  copper  band  is  now 
turned  to  shape  in  a  14-inch  engine  lathe  carrying  a  special 
forming  tool  that  covers  the  entire  width  of  the  band.  This 
operation  is  handled  at  the  rate  of  ninety  shells  per  day. 
The  shells  are  now  inspected  before  they  go  into  the  hands 
of  the  government  inspector.  The  inspection  operation 
consists  in  checking  up  the  diameter  of  the  band  and  the 
ogive  to  see  that  they  are  held  tightly  in  place.  The  shell  is 
stamped  on  a  Noble  &  Westbrook  stamping  machine.  The 


Fig.  63.     Spraying   Interior  and   Exterior  of  Shell  with  Copal   Varnish 

stamp  is  in  the  form  of  a  roll  that  is  passed  over  the  end 
of  the  shell,  pressure  being  applied  by  means  of  a  foot- 
treadle.  Prior  to  the  varnishing  which  follows,  the  shells 
are  washed,  after  which  they  are  dried. 

Varnishing  Interior  and  Exterior  of  Serbian  Shells.  — 
The  shells  now  go  to  the  lacquering  and  spraying  depart- 
ment where  they  are  sprayed  inside  and  outside  and  painted 
on  the  outside  previous  to  shipment.  For  the  spraying  of 
the  outside  of  the  shell,  a  special  De  Vilbiss  spraying  torch 
is  used  as  shown  to  the  right  in  Fig.  63,  whereas  the  inter- 
nal diameter  is  sprayed  on  a  special  machine  shown  in  the 


96  MACHINING   SERBIAN   SHELLS 

background  of  the  same  illustration.  Copal  varnish  is  used 
for  spraying;  this  prevents  the  high-explosive  from  coming 
into  contact  with  the  shell. 

Internal  Spraying  Machine.  —  The  operation  of  the  inter- 
nal spraying  device  is  more  clearly  shown  in  Fig.  64.  For 
this  operation  the  shell  A  is  placed  on  two  pairs  of  rollers 
B,  which  are  rotated  by  a  one-half  horsepower  electric  mo- 
tor. The  shells  revolve  at  the  rate  of  300  R.  P.  M.  and  they 
are  placed  on  the  rollers  and  removed  from  them  after  the 
spraying  is  done  and  while  the  rollers  are  still  in  motion. 


Fig.  64.     De  Vilbiss  Spraying   Machine  for  coating   Interior  of   High-explosive 

Shells 

The  rollers  are  driven  by  means  of  a  chain  from  the  motor 
through  a  countershaft.  The  operation  of  the  spraying 
member  of  the  machine  is  as  follows :  With  the  rollers  in 
motion  and  the  machine  in  the  position  shown  in  Fig.  64, 
lever  C  is  thrown  to  the  left  to  start  the  machine ;  this  re- 
leases a  catch  that  holds  lever  D  in  a  neutral  position.  The 
releasing  of  the  catch  allows  a  coil  spring  to  pull  lever  D 
into  the  position  shown,  this  lever  being  connected  to  the 
valve  E.  When  this  valve  is  operated,  the  air  passes 
through  it  to  a  cylinder  provided  with  a  piston,  the  forward 
motion  of  which  operates  a  cone  clutch  that  starts  carriage 


MACHINING  SERBIAN   SHELLS 


97 


F  moving  to  the  right.  When  the  carriage  F  strikes  stop 
H,  the  rod  upon  which  it  is  held  moves  forward  with  the 
carriage  until  the  coil  spring  is  pulled  over  the  center  line 
of  lever  D,  at  which  point  valve  E  is  operated  to  return  the 
carriage.  At  the  same  time  that  carriage  F  starts  to  move 
to  the  left,  the  air  valve  starts  the  spraying  device  G. 

There  are  two  noz- 
zles in  the  end  of  torch 
/  that  throw  a  stream 
of  varnish  in  two  di- 
rections. The  end  of 
the  shell  as  well  as  the 
sides  are  covered  as 
the  carriage  moves  to 
the  left.  The  varnish 
or  other  material  used 
flows  down  through 
the  flexible  metal  hose 
J  from  a  five-gallon 
container  suspended 
above  the  machine. 
When  the  spraying 
torch  reaches  the  point 
where  the  shoulder  of 
the  ogive  is  coated,  a 
cam  mounted  on  the 
bed  of  the  machine 
trips  the  air  valve  K, 
which  stops  the  spray- 
ing. This  valve  is  in 
circuit  with  the  valve 
that  starts  the  spray 
so  that  the  air  passes  through  both  of  them.  (Valve  K  is 
opened  on  the  forward  stroke  by  cam  L,  but  the  other  valve 
is  closed  at  that  time  and  the  spray  does  not  start.)  The 
carriage  continues  to  the  left  until  it  strikes  stop  M,  which 
moves  the  rod  N  back  to  the  point  where  the  lever  D  is 


Fig.  65.       De  Vilbiss  Spraying  Device  used  in 
coating   Exterior  of  High-explosive  Shells 


98 


MACHINING  SERBIAN  SHELLS 


pulled  back  by  the  spring.  A  trip  serves  as  a  stop  to  hold 
lever  D  in  a  neutral  position  until  it  is  again  thrown.  The 
throwing  of  lever  D  into  the  neutral  position  releases  the  air 
pressure  on  the  piston  holding  the  clutch  in  engagement, 
and  a  spring  pushes  the  clutch  out,  stopping  the  motion  of 
the  carriage.  The  production  is  400  shells  per  day. 

External  Spraying  Machine.  —  The  special  De  Vilbiss  ma- 
chine for  spraying  the  exterior  of  high-explosive  shells  is 
shown  in  Fig.  65.  The  spraying  of  the  outside  is  done  after 

the  inside  has  been 
sprayed.  In  spraying, 
the  shell,  as  shown  in 
Fig.  65,  is  placed  on  a 
vertical  revolving 
spindle  which  is  driven 
by  a  one-sixth  horse- 
power electric  motor 
at  a  speed  of  about 
250  R.  P.  M.  through 
a  belt  and  friction 
diskdrive.  The 
amount  of  spray  is  ad- 
justed by  changing 
the  position  of  the 
wheel  which  engages 
with  the  friction  disk. 
Lever  A  serves  to 
move  the  wheel  in  and 
out  of  engagement  and 
is  used  to  automatically  stop  and  start  the  machine  between 
the  spraying  of  the  shells.  The  adjustable  guard  B  is 
mounted  on  post  C  and  swings  in  against  a  stop  which  pulls 
it  into  position  and  covers  the  copper  driving  band  of  the 
shell,  protecting  it  from  the  varnish.  The  shell  is  sprayed, 
while  revolving,  with  a  De  Vilbiss  standard  type  L  "Aeron" 
shown  at  D,  the  operator  holding  this  device  in  his  hand 
as  shown  in  Fig.  63.  The  exhaust  fan  E  removes  the  va- 
pors caused  by  the  spraying  operation.  This  fan  is  oper- 
ated by  a  one-half  horsepower  motor,  entirely  enclosed  to 


Fig.  66. 


Painting  Exterior  of  High-explosive 
Shells 


MACHINING  SERBIAN  SHELLS  99 

protect  it  from  the  vapors,  and  the  motor  is  automatically 
cooled  by  the  clean  air  being  drawn  through  it  by  the  action 
of  the  fan.  The  production  on  this  machine  is  between  400 
and  500  shells  per  day. 

Painting  and  Drying  Shells.  —  After  spray  ing,  the  shells  are 
placed  in  a  Steiner  baking  oven  heated  to  300  degrees  F. 
(about  149  degrees  C.) ,  where  the  shells  are  baked  for  eight 
hours.  They  are  then  taken  to  the  Canadian  Fairbanks- 
Morse  painting  machine  shown  in  Fig.  66  where  they  are 
given  a  coat  of  yellow  paint.  This  painting  machine  con- 
sists of  a  stand  on  which  there  are  six  spindles,  each  of 
which  rotates  continuously.  The  shells  are  placed  upon  the 
spindles,  and,  as  they  rotate,  the  painter  holds  his  brush  on 
the  shell  and  applies  the  yellow  paint.  The  band  is  not 
painted.  One  man  can  handle  250  shells  per  day  with  this 
machine,  although  it  is  generally  used  with  a  battery  of  two 
painters  and  one  cleaner,  when  the  average  production  is  750 
shells.  Once  more  the  shells  are  placed  in  drying  ovens 
that  are  kept  at  a  temperature  of  150  degrees  F.  (about  66 
degrees  C.),  and  ten  hours  in  these  ovens  completes  the 
drying  of  the  shell;  it  would  require  twenty  hours  to  dry 
in  the  atmosphere.  After  drying,  the  shells  are  wrapped 
in  oil  paper  and  packed  ready  for  shipment. 


CHAPTER  VI 

MACHINING  FRENCH  120-MILLIMETER   (4.72-INCH) 

SHELLS 

THE  following  description  applies  to  the  manufacture  of 
the  French,  120-millimeter,  high-explosive  shell,  which  is 
made  from  a  seamless  steel  forging  of  the  proportions  shown 
at  A,  Fig.  67.  The  forging  is  machined  to  the  shape  shown 
at  B  and  is  then  nosed-in,  after  which  a  second  series  of 
operations  is  performed,  bringing  it  to  the  shape  shown 
at  C.  The  first  operation  is  to  pickle  the  forgings  to  re- 
move the  scale;  this  is  done  in  a  solution  made  up  of  sul- 
phuric acid  1  part,  water  10  parts.  The  temperature  of 
this  solution  should  not  be  raised  above  150  degrees  F. 
(about  66  degrees  C.),  as  a  higher  temperature  produces 
fumes  that  are  very  annoying.  The  forgings  are  pickled 
in  this  solution  for  one  hour  and  then  washed  in  a  bath 
of  hot  lime-water  to  remove  all  traces  of  the  acid. 

Sorting  and  Grinding  Base  End.  —  The  next  operation 
consists  in  sorting  the  forgings  for  size,  with  particular  ref- 
erence to  the  diameter  of  the  cavity.  The  forgings  are 
received  in  the  plant  in  three  lots :  Those  exactly  94  milli- 
meters (3.7  inches),  those  below,  and  those  above  this  di- 
mension. As  a  certain  thickness  of  wall  must  be  maintained 
in  this  shell,  the  variation  on  the  inside  diameter  of  the 
forging  is  carried  to  the  external  diameter,  and  on  forgings 
in  which  the  cavity  is  larger  than  the  exact  size  of  94  milli- 
meters, the  external  diameter  is  made  slightly  larger  to  al- 
low for  this.  It  is  therefore  necessary  that  the  forgings 
be  sorted  and  machined  in  different  lots.  After  sorting, 
they  are  taken  to  the  Gardner  double-spindle  disk  grinder 
shown  in  Fig.  68,  where  the  projection  on  the  closed  end  is 
surfaced  for  centering.  Here  the  forging  is  held  in  a  spe- 
cial cradle  fixture  fastened  to  the  swinging  table  and  is  held 

100 


MACHINING  FRENCH   SHELLS 


101 


in  place  by  a  clamp  as  shown.  The  wheel  used  is  a  car- 
borundum cylinder  wheel,  16  inches  in  diameter,  with  a 
2-inch  rim.  The  speed  of  the  wheel  is  1200  R.  P.  M.,  the 
amount  of  stock  removed  from  1/32  to  1/16  inch,  and  the 
production  about  thirty  per  hour.  The  complete  order  of 
operations  is  given  in  Table  IV. 


U  ---  112  ---  J 

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4.7624  |<-60.3239->{    A 


B 


-»|  25.3996  | 
-121.93  ±0. 87— H 

C     Machinery 


Fig.  67.     Principal  Dimensions  of  Forging  and  Condition  of  French 

120-millimeter  High-explosive   Shell  after  First  Series  of 

Machining  Operations 

Cutting  Off  Open  End  of  Shell  and  Centering  Closed  End. 
-  From  the  disk  grinder,  the  f  orgings  are  taken  to  the 
lathe  shown  in  Fig.  69,  where  the  open  end  is  cut  off,  bring- 
ing the  forging  to  the  desired  length.  The  f  orgings  are 
held  on  an  expanding  mandrel  operated  by  a  special  air 
chuck  as  shown  in  Fig.  70.  Here  the  forging  is  shown,  by 
heavy  dotted  lines,  gripped  near  the  open  end  by  an  ex- 


102 


MACHINING  FRENCH   SHELLS 


Fig.   68.     Grinding    Base    End   of   French   129-millimeter   High-explo- 
sive Shell   Forgings  in  a  Gardner  D.sk  Grinder 


Fig.  69.     Cutting  off  Open   End  of  High-explosive  Shell   Forging 


H  O 
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104 


MACHINING  FRENCH  SHELLS  105 

spindle.  For  this  operation,  the  work  is  rotated  at  70  feet 
surface  speed  and  the  production  is  fifteen  per  hour.  After 
cutting  off,  the  shell  is  gaged  to  length  by  the  gage  shown 
in  Fig.  71.  This  gage  has  graduations  on  the  bar,  giving 
the  limits. 

The  centering  of  the  closed  end  is  accomplished  in  an  en- 
gine lathe  as  shown  in  Fig.  72.  The  lathe  is  provided  with 
a  Hannifin  air  chuck,  operating  an  expanding  mandrel  of 


Fig.  71.     Gage  used   in  testing   Length  of  Trimmed   Forgings 

the  type  shown  in  Fig.  73,  on  which  the  forging  is  held. 
This  mandrel  differs  somewhat  in  construction  from  that 
shown  in  Fig.  70  in  that,  in  addition  to  clamping  the  forg- 
ing, it  centers  it  accurately  from  the  internal  diameter.  In 
construction,  this  mandrel  comprises  a  main  sleeve  A,  which 
is  screwed  onto  the  spindle  of  the  machine,  and  inside  of 
which  passes  a  rod  B  and  sleeve  C.  Rod  B  and  sleeve  C 


106  MACHINING  FRENCH   SHELLS 

are  provided  with  tapered  bearings  that  operate  clamp- 
ing blocks  D  and  E  against  the  tension  of  flat  springs  F 
and  G.  These  blocks  are  located  equidistantly  around  the 
circumference  of  the  mandrel 'and  engage  the  interior  of 
the  forging  near  the  base  end  and  about  11/2  inch  from 


Fig.  72.     Centering  Closed   End  of  Forging 

the  open  end,  respectively.     Sleeve  C  of  the  chuck  is  forced 
forward  when  rod  B  is  drawn  back  and  vice  versa. 

Centering  is  done  with  a  United  States  electric  drill  held 
in  a  cradle  A,  Fig.  72,  which  is  fastened  to  the  cross-slide 
of  the  lathe  and  consequently  moves  with  it.  The  center- 
ing tool  is  guided  by  a  plate  B  fastened  to  the  cross-slide 
which  holds  the  tool  in  line  with  the  axis  of  the  machine 


107 


108  MACHINING   FRENCH    SHELLS 

and  drill  spindles.  The  center  hole  is  drilled  and  counter- 
sunk %  incn  deep.  The  work  is  rotated  at  25  feet  surface 
speed  and  the  drill  at  175  surface  feet;  the  production  is 
forty-five  shells  per  hour. 


Fig.  74.     Facing  off  Closed   End  of  Forging  to   Lengtfi 

Facing  Off  Closed  End  and  Gaging  for  Length.  —  After 
centering,  the  closed  end  of  the  forging  is  faced  off  to  the 
required  length,  as  shown  in  Fig.  74,  the  forging  being  held 
on  an  expanding  air-operated  mandrel  of  the  type  shown  in 
Fig.  73.  The  desired  length  is  secured  by  a  swinging  tool- 
setting  gage  A  held  in  a  bracket  fastened  to  the  bed  of  the 


MACHINING  FRENCH    SHELLS 


109 


lathe.     In  facing,  from  !/2  to  %  inch  of  stock  is  removed; 
the  work  is  rotated  at  70  surface  feet  per  minute  and  the 
feed  is  by  hand.     The  production  is  six  shells  per  hour. 
The  next  operation  consists  in  gaging  the  trimmed  forg- 


Fig.  75. 


Gaging  Total  Length  of  Trimmed  Forging  Prior  to 
Turning 


ings  for  over-all  length,  as  shown  in  Fig.  75.  The  gage  used 
consists  of  a  plate,  two  pillars,  and  a  cross  bar.  The  plate 
has  a  slot  so  that  the  teat  on  the  end  of  the  shell  does  not 
interfere  with  the  correct  measurement  of  the  over-all 
length.  The  gage  used  in  testing  the  length  of  the  shell 


110 


MACHINING  FRENCH   SHELLS 


after  cutting  off  the  open  end  is  also  shown  at  the  right. 
The  allowable  limit  on  length  is  4  millimeters. 

Rough-turning  External  Diameter. —  The  rough-turning 
of  the  external  diameter  is  accomplished  on  a  "Lo-swing" 
lathe  as  shown  in  Fig.  76.  Two  tools  are  used  for  this 
operation  and  remove  about  3/16  inch  of  stock  from  the 


Fig.  76.     Rough-turning  External  Diameter  In  a  "Lo-swing"  Lathe 

diameter.  One  tool  starts  at  the  center  of  the  forging  while 
the  other  works  from  the  closed  end,  so  that  the  time  re- 
quired to  turn  the  entire  length  of  the  shell  is  only  equal 
to  that  which  would  be  necessary  to  turn  one-half  the 
length  with  one  tool.  For  this  operation,  the  shell  is  held 
on  an  expanding  mandrel  of  the  type  shown  in  Fig.  73. 


MACHINING  FRENCH    SHELLS 


111 


The  first  cutting  tool  turns  straight  for  a  short  distance 
until  it  approaches  the  nose,  when  it  is  backed  out  to  en- 
large the  shell  at  that  portion  where  it  is  nosed-in.  The 
shells  are  turned  in  this  operation  to  within  2  millimeters 
(0.0787  inch)  of  the  finished  size,  the  remainder  being  left 


Fig.  77.     Nosing-in  Open  End  of  Shell  in  a  Beaudry  Hammer 

for  grinding.  The  test  for  diameter  is  then  made  with  a 
set  of  Johansson  gages,  after  which  the  shell  is  heated  for 
nosing-in.  The  production  is  four  per  hour. 

Nosing-in  Open  End  and  Heat-treating. —  For  nosing-in, 
the  shell  is  heated  for  a  distance  of  six  inches  back  from 
the  open  end  in  the  Frankfort  furnace  shown  in  the  back- 


112 


MACHINING  FRENCH   SHELLS 


ground  in  Fig.  77.  The  shells  are  left  in  the  furnace  for 
thirty  minutes  and  heated  to  a  temperature  of  1600  degrees 
F.  (about  870  degrees  C.).  The  furnace  is  heated  by  nat- 
ural gas,  and  holds  ten  shells  at  one  time.  The  nosing-in 
operation  is  accomplished  in  a  500-pound  Beaudry  ham- 
mer, as  shown  in  Fig.  77.  For  this  work  four  men.  are 
required.  One  rotates  the  shell  on  its  axis;  another  feeds 
the  shell  into  the  hammer  dies,  which  are  split  and  of  the 
right  shape ;  the  third  operates  the  hammer ;  and  the  fourth 
takes  the  nosed-in  shell  out  of  the  hammer  and  brings  an- 


Fig  78.     Heat-treating  Furnace  and  "Brush"  for  removing  Scale 
prior   to    immersing    Heated    Shell    in    Cooling    Bath 

other  one  to  the  power  hammer  ready  for  nosing-in.  The 
nosing-in  is  started  with  light  blows,  so  as  to  make  the 
metal  flow  as  evenly  as  possible;  the  blows  are  then  in- 
creased in  severity  until  the  shell  has  received  about  twenty- 
five  blows,  which  is  ordinarily  sufficient  to  complete  the  op- 
eration. An  improved  method,  however,  eliminates  one 
man  by  rotating  the  shell  on  its  axis  by  means  of  an  air 
drill.  The  production  is  thirty  per  hour. 

After  nosing-in,  the  shell  is  taken  to  a  lathe  where  it  is 
gripped  in  a  chuck,  the  nose  bored  out,  and  the  end  faced 
off  to  length.  The  next  operation  is  heat-treating,  the 


MACHINING  FRENCH    SHELLS  113 

heating  being  done  in  a  Frankfort  furnace  of  the  type  shown 
to  the  left  in  Fig.  78.  The  shell  is  left  in  the  furnace  for 
twenty-five  minutes  at  a  temperature  of  1800  degrees  F. 
(about  980  degrees  C.).  As  soon  as  the  shell  reaches  the 
desired  temperature,  it  is  quickly  removed  from  the  furnace 


Fig.  79.     Dipping   French    High-explosive   Shells   in   Special   Cooling 

Bath 

and  placed  in  the  cooling  bath,  shown  in  Fig.  79  and  in 
detail  in  Fig.  80.  Formerly  the  brushing  device  shown  in 
the  foreground  of  Fig.  78  was  used  to  remove  the  scale, 
but  this  has  been  found  unnecessary.  Each  cooling  bath 
accommodates  only  one  shell  and  is  so  arranged  that  the 
water  circulates  inside  the  cavity  as  well  as  around  the  ex- 


114 


MACHINING  FRENCH   SHELLS 


ternal  circumference.     The  shells  are  left  in  the  cooling 
bath  for  five  minutes,  after  which  tempering  follows.     The 


Machinery 


Fig.  80.     Details  of  Cooling   Bath  shown  in   Fig.  79 

quenching  device  shown  in  Fig.  80  does  not  provide  for 
rotating  the  shell  when  cooling.  An  improved  device  incor- 
porates a  rotating  table  for  revolving  the  shell  and  thus 


MACHINING  FRENCH   SHELLS  115 

obtaining  a  more  uniform  hardness.  The  tempering  opera- 
tion, which  follows,  is  accomplished  by  heating  the  shell 
to  970  degrees  F.  (about  520  degrees  C.)  in  a  Frankfort 
furnace  and  then  taking  it  out  and  allowing  it  to  cool  off  in 
the  air. 

Inspecting  for  Hardness.  —  The  final  inspection  for  hard- 
ness is  accomplished  by  means  of  a  hydraulic  testing  ma- 
chine, working  on  the  Brinell  ball  principle,  as  is  shown  in 
Fig.  81.  The  ball  used  is  10  millimeters  in  diameter,  and 
the  pressure  is  3000  kilograms  (6613.8  pounds)  for  a  pe- 
riod of  fifteen  seconds.  The  diameter  of  the  impression 


Fig.  81.     Testing  Hardness  of  French  120-millimeter  High-explosive 

Shells 

made  with  this  ball  must  be  3.4  millimeters  (0.1139  inch)  ; 
this  corresponds  to  a  hardness  on  the  Brinell  chart  of  321. 
After  this  testing  operation,  the  shells  are  ready  for  grind- 
ing. This  Brinell  test  factor  indicates  an  ultimate  strength 
of  about  124  kilograms  per  square  millimeter. 

Pickling  and  Drying  Partly  Machined  Shells. — After 
heat-treatment  and  testing  for  hardness,  the  shells  are 
pickled  to  remove  the  scale  formed  in  heat-treating,  and 
dried  before  any  further  machining  operations  are  per- 
formed on  them.  For  pickling,  the  shells  are  placed,  open 
end  up,  in  a  wooden  rack  and  are  immersed  for  forty-five 


20:= 

W — via 


116 


MACHINING  FRENCH    SHELLS 


117 


minutes  in  a  bath  consisting  of  ten  parts  water  to  one  part 
sulphuric  acid,  and  when  lifted  out  are  tipped  so  that  the 
pickling  solution  runs  out  quickly.  After  immersing  in  the 
acid  bath,  the  shells  are  washed  in  a  solution  of  strong  lime- 
water,  then  in  clear  running  water,  and  then  dried  in  a  coke 
furnace,  which  is  heated  to  400  degrees  F.  (about  200  de- 


Fig.  83.     Boring  and  threading  Open   End  of  Shell  on  Jones  & 
Lamson   Single-spindle  Turret   Lathe 

grees  C.).  This  furnace  is  24  inches  wide,  12  inches  high, 
and  48  inches  long,  and  is  tilted  from  the  floor  so  that  the 
shells,  when  fed  in  at  one  end,  roll  down  and  out  of  the 
other.  It  holds  ten  shells,  which  are  left  in  it  for  forty 
minutes,  after  which  they  are  taken  out  and  allowed  to 
cool  in  the  air. 


118 


MACHINING  FRENCH    SHELLS 


Boring  and  Threading  Nose  End. —  Following  the  pick- 
ling of  the  partly  machined  shell,  the  first  operation  consists 
in  recentering  the  base  end,  which  is  done  on  a  Williams 
Tool  Co.  cutting-off  machine  that  has  been  fitted  up  for 
centering.  Here  a  light  cut  is  taken  to  true  up  the  center ; 
the  time  required  is  about  ten  seconds  per  shell. 


Fig.  84.     Finish-turning   External   Diameter  in  a  "Lo-swing"   Lathe 
at  the  Rate  of  Four  Shells  per  Hour 

Following  this,  the  shells  are  taken  to  the  Jones  &  Lamson 
turret  lathe  shown  in  Fig.  83.  For  this  operation,  the  work 
is  held  in  a  "Whiton"  chuck  and  supported  by  a  three-roll 
steadyrest.  The  operation  consists  in  rough-boring  the 
hole  in  the  nose,  finish-boring  hole  with  an  expanding  bor- 


MACHINING  FRENCH   SHELLS 


119 


ing-bar,  reaming  to  43.6  millimeters  in  diameter,  rough-  tap- 
ping with  Murchey  collapsible  tap,  finish-tapping  with 
Murchey  tap.  For  boring,  the  work  is  rotated  at  50  surface 
feet  per  minute,  and  for  tapping  at  30  feet  per  minute.  The 
production  is  seven  shells  per  hour  from  each  machine.  The 
shells  are  now  removed  from  the  chuck  and  the  thread  fin- 
ished to  exact  size  by  means  of  a  master  tap ;  this  is  really 
an  inspection  operation.  The  shells  are  then  washed  in  a 
steam  bath  to  remove  all  the  oil  and  grease  and  are  then 
dried  thoroughly.  Hardened  center  plugs  are  afterwards 


Fig.  85.     Grinding  Body  of  Shell  on  Norton  Plain  Grinding  Machine 

screwed  into  the  open  end  of  the  shell  to  serve  as  a  center 
point  when  grinding  and  turning  the  external  surface  in 
subsequent  operations. 

Finish-turning  External  Diameter  of  Shell. —  The  finish- 
turning  operation  is  done  on  the  "Lo-swing"  lathe  shown  in 
Fig.  84.  Here  two  tools  are  used  to  finish  the  straight  por- 
tion; and  when  these  have  traveled  about  6  inches  on  the 
shell,  a  third  tool  A  turns  the  radius  on  the  nose.  Another 
tool,  not  shown,  turns  the  band  groove  to  width  and  depth, 
then  an  under-cutting  tool  finishes  the  under-cut,  and  finally 
the  groove  is  knurled.  The  last  operation  is  to  bevel  the 


120 


MACHINING  FRENCH    SHELLS 


closed  end  with  tool  B.  When  a  copper  ring  is  used  for 
the  rifling  band,  only  one  side  of  the  groove  is  dovetailed, 
but  when  a  copper  strip  is  used,  both  sides  must  be  dove- 
tailed. For  the  various  turning  operations,  the  work  is 
rotated  at  a  surface  speed  of  50  feet  per  minute,  and  the 
feed  for  the  external  straight  turning  is  0.020  inch  per 
revolution.  The  production  is  four  shells  per  hour. 

Grinding  External  Diameter.  —  In  the  grinding  operation 

that  follows  finish- 
turning  and  illus- 
trated in  Fig.  85, 
about  from  0.020  to 
0.030  inch  of  material 
is  removed  from  the 
diameter  of  the  shell. 
The  machine  is  a  Nor- 
ton plain  grinder  car- 
rying a  Norton  alun- 
dum  20-inch  diameter 
by  2-inch  face  wheel, 
grain  46,  grade  M,  ro- 
tated at  1275  R.  P.  M. 
The  grinding  is  done 
only  on  the  straight 
portion,  starting  at  a 
short  distance  from 
the  base  end,  and  pro- 
ceeds straight  until 
Fig.  se.  pressing  on  copper  Driving  Band  the  enlargement  near 

in  a  West  Tire  Setter  Co.   Banding  Press          the     noge     ^     reached. 

The  wheel  is  then  backed  away  from  the  work  the  required 
distance,  and  the  straight  portion  finished  on  the  nose  to  the 
point  where  the  radius  merges.  Owing  to  the  length  of  the 
work,  the  traverse  method  of  grinding  is  used.  The  wheel  is 
trued  up  after  grinding  every  three  shells.  The  production 
is  eight  shells  per  hour  from  each  machine. 

Pressing  On  and  Turning  Copper  Bands.  —  When  the 
copper  band  is  of  the  ring  type,  the  pressing  on  is  done  in 
a  West  Tire  Setter  hydraulic  banding  press,  as  shown  in 


MACHINING  FRENCH   SHELLS 


121 


Fig.  86.  The  inside  diameter  of  this  band  is  slightly  larger 
than  the  external  diameter  of  the  shell,  and  is  located  in  the 
correct  position  by  means  of  the  compressing  dies,  six  of 
which  are  held  in  the  machine.  It  requires  from  two  to 
three  squeezes  to  finish  the  pressing,  and  the  production  is 
twenty  shells  per  hour.  Before  pressing  on,  the  copper 


Fig.  87.     Turning   Copper   Driving   Band 


Fig.  88.     Weighing   French  120-millimeter  High-explosive  Shell 

rings  are  heated  to  a  dark  red,  then  dipped  in  water  and 
cooled  to  the  temperature  of  the  surrounding  atmosphere. 
Following  pressing  on  of  the  band,  the  shells  are  taken  to  a 
16-inch  engine  lathe,  as  shown  in  Fig.  87.  The  first  opera- 
tion is  to  take  a  rough  cut  over  the  external  diameter  of 
the  copper  band  with  a  turning  tool,  after  which  a  form 


122  MACHINING  FRENCH   SHELLS 


Fig.  89.     Gaging  External  Diameter  and  Thread  in  Nose 


Fig.  90.     Gaging   Contour  of   French   120- millimeter   High-explosive 

Shell 


MACHINING  FRENCH   SHELLS 


123 


tool  finishes  the  copper  band  to  shape  and  diameter.  The 
production  is  twenty  per  hour. 

After  turning  the  copper  band,  the  center  projection  is 
cut  off  the  closed  end  of  the  shell  on  a  Williams  Tool  Co. 
cutting-off  machine  at  the  rate  of  twenty-four  per  hour. 
The  center  plug  in  the  open  end  of  the  shell  is  also  removed, 
leaving  the  shell  in  a  suitable  condition  for  weighing  and 
inspecting. 

Inspection.  --  The  first  inspection  is  for  weight  as  shown 
in  Fig.  88.  The  correct  weight  is  16  kilograms,  750  grams, 


Fig.  91.     Gaging  Angle  on   Base  End  of  Shell 

and  the  tolerance  is  ±  200  grams  (35  pounds,  6.97  ounces, 
±  7.05  ounces).  The  first  gaging  test  made  is  that  for 
"bulge  diameter."  In  this  test,  illustrated  in  Fig.  89,  two 
ring  gages  are  used.  The  diameter  over  the  bulge  is  119.6 
millimeters  plus  0.00  millimeter,  minus  0.15  millimeter.  The 
"go"  size  must  pass  over  the  bulge,  whereas,  the  "not  go" 
size  must  stop  on  it,  as  shown.  The  next  test  is  made  over 


124 


MACHINING  FRENCH   SHELLS 


the  copper  band ;  for  this,  snap  gages  of  the  horseshoe  type 
are  used.  The  limits  are  121.5  millimeters  plus  0.15,  minus 
0.00  millimeter.  The  third  test  is  for  over-all  length, 
which  is  accomplished  by  means  of  a  gage  similar  to  that 
illustrated  in  Fig.  75.  With  a  gage  of  a  similar  kind,  the 
thickness  of  the  closed  end  is  measured  from  the  nose.  The 
next  test  is  the  diameter  across  the  nose.  This  is  made 


Fig.  92.     Testing  for  Strength  in  a  Metalwood  Hydraulic  Press 

with  a  flat  gage  and  the  limits  are  55  millimeters  plus  1.0, 
minus  0.00  millimeter.  The  master  thread  gage  is  next 
screwed  into  the  nose  to  see  if  the  thread  is  correct ;  after 
this  the  plug  is  tried  for  diameter  at  root  of  thread ;  these 
gages  are  all  shown  in  Fig.  89.  The  next  test  is  for  the 
contour,  which  is  made  as  shown  in  Fig.  90.  A  long  flat 
gage  that  covers  the  entire  length  of  the  shell  and  also  the 
contour  at  all  points,  when  laid  across  the  shell  as  illus- 


MACHINING  FRENCH  SHELLS 


125 


trated,  shows  whether  the  shell  has  been  turned  and  fin- 
ished to  the  correct  shape  or  not.  Every  point  on  the  shell 
must  check  up  to  the  templet.  The  next  test  consists  in 
testing  the  angle  at  the  closed  end  of  the  shell,  as  shown  in 
Fig.  91.  The  maximum  diameter  is  118.5  plus  0.25  milli- 
meter, and  the  minimum  diameter  is  110.5  millimeters. 

Testing  for  Concentricity.  —  The  next  important  test  is 
for  concentricity.  In  this  test,  as  illustrated  in  Fig.  93,  a 
counterweight  gage  A 
having  two  arms  and 
counterweighted  o  n 
one  end  is  fastened  to 
the  base  end  of  the 
shell.  The  shell  rests 
on  hardened  strips 
fastened  to  a  cast-iron 
plate  and  is  located  at 
right  angles  to  the 
hardened  pieces  by 
pins  driven  into  the 
plate.  It  is  then  rolled 
over  and  must  balance 
perfectly  when  the 
gage  is  in  place.  The 
heavy  side  of  the  shell 
is  first  found  by  rotat- 
ing it  on  the  parallel 
ways  and  then  the 
weight  is  located  on 
the  light  side.  The  moment  of  rotation  must  equal  the 
amount  of  eccentricity  from  the  center  of  gravity  times 
the  weight  of  the  shell,  as  worked  out  from  the  formula : 

WS  =  PR 
in  which  W  =  weight  of  shell ; 

P  =  weight  used  on  stem  of  gage ; 

R  =  distance  from  center  of  shell  to  center  of 
weight  P; 


Fig.  93.     Gaging  Concentricity  of  Shell 


126  MACHINING   FRENCH    SHELLS 

S  =  maximum  eccentricity  from  center  of  gravity, 
which  on  this  size  of  shell  is  0.7  millimeter. 

As  Wy  P,  and  R  are  known,  S  may  be  solved  in  the  for- 
mula given.  If  S  is  found  to  be  0.7  millimeter  or  less,  the 
shell  is  passed.  If,  however,  S  is  found  to  be  more  than 
0.7  millimeter,  the  eccentricity  is  too  great ;  P  and  R  may  be 
standardized  for  the  maximum  eccentricity,  thus  avoiding 
calculating. 

Testing  French  High-explosive  Shells  for  Strength.  - 
Every  shell  after  machining  and  inspection  is  tested  for 
strength  in  a  hydraulic  press  of  the  type  shown  in  Fig.  92 ; 
this  particular  machine  is  made  by  the  Metalwood  Mfg.  Co., 
Detroit,  Mich.  Previous  to  testing,  the  shells  are  filled 
with  water  and  placed  in  the  machine.  A  pressure  equal 
to  650  kilograms  per  square  centimeter  (9500  pounds  per 
square  inch)  is  then  maintained  on  every  shell  for  about 
ten  seconds,  after  which  the  shell  must  show  no  leaks  nor 
cracks.  Following  the  testing  operation,  the  shell  is  ex- 
amined for  cracks,  etc.,  and  is  then  inspected  by  French 
officials.  One  shell  in  every  hundred  is  given  every  test 
by  an  official.  The  last  operation  consists  in  greasing  and 
packing  the  shells  ready  for  shipment. 


CHAPTER  VII 


MACHINING  BRITISH  HOWITZER  SHELLS 

THE  British,  4.5-inch,  howitzer,  high-explosive  shell, 
shown  in  Fig.  94,  starts  with  a  cast  billet  about  three  feet 
long,  which  is  subsequently  cut  into  shorter  lengths  and 
forged  to  approximate  shape.  There  are  about  thirty-two 
machining  and  inspection  operations  on  this  shell,  and  the 
average  time  required  to  produce  one  shell  complete  and 
ready  for  shipment  is  one  hour,  thirty-six  minutes.  The 


Machinery 


Fig.  94.     British  4.5-inch  Howitzer  High-explosive  Shell 

equipment  used  for  this  purpose,  however,  was  not  origin- 
ally laid  out  for  handling  this  work;  in  fact,  the  only  special 
equipment  purchased  to  turn  a  car  shop  into  a  shell  plant 
was  small  tools  and  a  few  attachments  for  engine  lathes. 
The  order  of  the  various  operations  is  as  follows :  The 
shell  is  marked  off  and  the  amount  of  material  to  be  re- 
moved from  each  end  is  indicated.  The  open  end  is  then 

127 


128 


MACHINING  HOWITZER  SHELLS 


cut  off,  as  shown  in  Fig.  95,  in  an  axle  lathe  that  has  been 
fitted  up  for  this  work.  This  axle  lathe  is  of  the  double- 
head  type,  so  that  two  men  can  work  on  one  machine.  The 
production  is  250  in  ten  hours.  The  wall  of  the  forging 
is  about  13/16  inch  thick,  the  cut-off  tool  %  inch  wide,  and 
the  speed  15  R.  P.  M. ;  the  cutting  tool  is  fed  in  by  hand. 


Fig.  95.     Cutting  off  Open   End  of  Forging 

Facing  and  Rough-boring.  —  The  second  operation  con- 
sists in  facing  off  the  closed  end  in  a  boring  mill  where 
twenty-four  of  the  f orgings  are  held  in  a  fixture ;  two  tools 
are  used.  The  depth  of  cut  is  14  inc^  an(*  the  feed  1/16 
inch  per  revolution.  The  table  of  the  machine  is  operated 
at  120  R.  P.  M.  and  the  production  is  about  220  in  ten  hours. 


MACHINING  HOWITZER  SHELLS 


129 


The  third  operation  consists  in  rough-boring  the  interior 
to  3%  inches  in  diameter  in  a  four-spindle  rail  drill  operated 
by  two  men,  as  shown  in  Fig.  96.  The  hole  is  9%  inches 
deep  and  is  finished  in  one  cut.  A  cutting  lubricant  known 
as  "Mystic,"  made  by  the  Cataract  Refining  Co.,  is  used 
to  keep  the  tools  cool.  The  shell  being  rough-bored  is  held 


Fig.   96. 


Boring  out  Cavity  of  4.5-inch   Howitzer  High-explosive 
Shell 


in  a  spring  collet  chuck  attached  to  a  slide  that  works  in 
guides  located  on  the  table.  The  boring  tools  are  rotated 
at  50  R.  P.  M.  and  the  spindle  moves  down  with  a  speed  of 
about  1/16  R.  P.  M.  The  production  is  240  in  ten  hours. 

The  fourth  operation  consists  in  centering  the  base  end 
in  an  18-inch  engine  lathe.     The  forging  is  held  on  an  ex- 


130  MACHINING  HOWITZER  SHELLS 

panding  mandrel  and  the  center  hole  in  the  base  end  is  first 
drilled  and  then  centered  with  a  centering  tool.  The  pro- 
duction is  400  in  ten  hours. 

Rough-turning.  —  The  fifth  operation  is  rough-turning  in 
an  axle  lathe.  The  shell  is  again  held  on  an  expanding 
mandrel  and  turned  up  for  a  distance  of  9*4  inches  from  the 
base  end.  The  feed  is  3/32  inch  per  revolution  and  the 
depth  of  cut  is  7/32  inch.  The  speed  of  the  work  is  50 
R.  P.  M.  The  production  is  140  in  ten  hours. 

Spot-drilling,  Bottoming,  and  Finish-boring.  —  The    sixth 


Fig.   97.     Finish-boring,   reaming   and  facing  4.5-inch    Howitzer 
High-explosive  Shell 

operation  consists  in  spot-drilling  on  the  inside  with  an 
end-cutter  on  a  28-inch,  upright,  drilling  machine.  The 
work  is  held  in  a  collet  chuck  and  about  %  inch  of  metal 
is  removed.  The  spot-drilling  tool  is  rotated  at  140  R.  P. 
M.,  and  is  operated  by  hand  feed ;  the  production  is  300  in 
ten  hours.  The  seventh  operation  consists  in  hogging  out 
the  pocket  at  the  bottom  with  a  form  cutter,  held  in  a  bor- 
ing-bar in  a  wheel  boring  lathe  of  the  vertical  type.  This 
tool  is  rotated  at  48  R.  P.  M.  and  just  cuts  at  the  bottom; 
it  is  operated  by  hand  feed.  For  this  operation  the  forg- 
ing is  held  in  an  expanding  collet  chuck  and  the  production 
is  sixteen  pieces  per  hour. 


MACHINING  HOWITZER  SHELLS  131 

The  eighth  operation  consists  in  chamfering  on  a  wheel 
boring  lathe  with  a  tool  that  chamfers  the  inside  of  the 
shell  at  the  mouth  only.  This  tool  is  rotated  at  48  R.  P.  M. 
and  chamfers  for  a  distance  of  about  1%  inch  down  into 
the  shell,  enlarging  the  shell  from  3%  to  4  3/16  inches. 
The  ninth  operation,  as  shown  in  Fig.  97,  consists  in  finish- 
boring  the  inside  of  the  shell  and  finish-chamfering  the 
mouth.  The  operation  is  to  bore  and  face  with  an  end 
facing  tool  that  is  located  from  the  bottom,  then  finish  the 
pocket  at  the  bottom  and  chamfer.  The  machine  used  is 


Fig.  98.     Waving  and  Under-cutting   Band  Grooves 

a  Bertram  26-inch  engine  lathe  provided  with  a  turret,  and 
the  shell  is  held  in  an  expanding  chuck  and  rotated  at  80 
R.  P.  M.  The  cuts  vary  from  1/32  inch  to  just  cleaning  up, 
and  the  production  is  eighty  in  ten  hours. 

Grooving  and  Waving.  —  The  tenth  operation  is  finishing 
the  nose  on  the  outside  diameter  with  two  tools.  The  first 
takes  a  straight  roughing  cut,  the  second  turns  the  radius, 
and  a  third  tool  held  in  the  same  toolpost  finish-chamfers 
the  end.  The  machine  used  is  a  New  Haven,  24-inch,  en- 
gine lathe.  The  center  on  the  tailstock  is  brought  in  to 
support  the  work,  which  is  also  held  in  a  three-jawed  chuck. 


132  MACHINING  HOWITZER  SHELLS 

The  work  rotates  at  60  R.  P.  M.  and  the  production  is  220 
in  ten  hours.  The  eleventh  operation  consists  in  taking  a 
finishing  cut  over  the  base,  roughing  out  the  band  groove, 
and  finishing  the  external  diameter  back  of  the  band  groove, 
on  a  New  Haven,  24-inch,  engine  lathe.  The  production 
is  twelve  per  hour.  The  work  is  rotated  at  60  R.  P.  M., 
and  one  turner  and  one  form  tool  are  used. 

The  twelfth  operation  is  waving  and  under-cutting  in  a 
New  Haven,  24-inch,  engine  lathe,  to  which  has  been  applied 
a  Bertram  waving  attachment,  as  shown  in  Fig.  98.  The 
work  is  held  in  a  chuck  of  the  three-jaw  type  and  is  sup- 
ported at  the  opposite  end  by  the  tailstock  center.  The 


Fig.  99.     Boring  out  Closed  End  of  Shell  for  Gas  Plug  and  threading 

waving  tools  are  operated  by  a  cam  on  the  face  of  the  chuck. 
The  work  is  rotated  at  40  R.  P.  M.  and  the  production  is 
twenty-five  per  hour. 

Nosing-in,  Boring,  and  Threading  Nose.  —  The  thirteenth 
operation  is  nosing-in,  which  is  done  in  a  Williams  &  White 
bulldozer.  The  shell  is  heated  in  a  furnace  to  a  white  heat 
and  is  nosed-in  in  one  blow.  It  requires  three  men  to  han- 
dle this  operation ;  one  looks  after  the  furnace  and  two  after 
the  machine.  The  production  is  400  in  twelve  hours.  Af- 
ter cooling,  the  shell  is  brought  back  to  the  machining  de- 
partment where  the  fourteenth  operation  is  performed. 
This  consists  in  boring  out  the  closed  end  of  the  shell  for 


MACHINING  HOWITZER  SHELLS  133 

the  gas  plug  and  threading  on  a  Jones  &  Lamson,  single- 
spindle,  flat-turret  lathe,  as  shown  in  Fig.  99.'  The  opera- 
tions are :  Drill  hole  1%  inch  in  diameter,  hog  out  with  a  flat 
cutter,  under-cut  and  face  with  a  combination  under-cutting 
and  facing  tool,  and  thread  with  a  Jones  &  Lamson  regular 
chasing  attachment.  The  work  for  all  operations  except 
threading  is  operated  at  30  surface  feet  per  minute,  and  the 
production  is  ten  per  hour. 

The  fifteenth  operation  consists  in  machining  the  nose 
on  a  Reed,  20-inch,  engine  lathe,  provided  with  a  turret 
attachment,  shown  in  Fig.  100.  The  operations  are :  Bore, 
taking  a  1/16-inch  cut  at  a  speed  of  50  R.  P.  M.,  and  face 
off  to  length,  rough  out  inside  radius  with  a  boring  tool, 


Fig.  100.     Boring,  facing  and  threading  Nose  End  of  Shell 

feeding  by  hand ;  finish  inside  radius  to  shape  with  a  form 
cutter;  and  tap  for  a  distance  of  2  inches  with  a  Murchey 
collapsible  tap.  The  production  is  nine  and  one-half  per 
hour. 

Finish-turning.  — For  the  sixteenth  operation  a  center 
plug  is  inserted  in  the  open  end  of  the  shell.  The  external 
diameter  is  then  turned  all  over  in  an  18-inch  Canadian 
Machinery  Corporation  lathe.  As  shown  in  Fig.  101,  two 
cutters,  which  are  held  in  the  toolpost,  are  used  for  finish- 
ing. The  cut  is  about  3/64  inch  deep,  and  the  operation  of 
the  tool-slide  is  controlled  by  a  forming  bar  at  the  rear. 
The  feed  of  the  tools  is  1/32  inch  per  revolution;  and  the 
speed,  100  R.  P.  M.  The  production  is  nine  per  hour. 


134  MACHINING  HOWITZER  SHELLS 

Miscellaneous  Operations.  —  The  seventeenth  operation 
is  sand-blasting  the  inside  with  an  air  nozzle  inserted  in  the 
shell;  the  production  is  about  200  in  ten  hours.  The  eigh- 
teenth operation  is  preliminary  inspection.  The  nine- 
teenth is  to  screw  in  the  base  plug,  and,  at  the  same  time, 
wrench  off  the  projection  with  a  heavy  wrench.  The  twen- 
tieth operation  is  to  face  off  the  plug  and  round  the  edges 
of  the  base  on  a  Canadian  Machinery  Corporation  18-inch 
engine  lathe.  The  operations  are:  Take  a  roughing  cut 
across  the  base,  roll  in  plate  with  a  plain  roller,  and  take  a 
finishing  cut  across  the  base.  For  these  operations  the  feed 


Fig.  101.     Turning   External   Diameter  to  Size  and  Shape 

is  by  hand  and  the  cuts  vary  in  depth  from  1/16  to  3/16 
inch.  The  speed  of  the  work  is  120  R.  P.  M.,  and  the  pro- 
duction is  fifteen  per  hour. 

The  twenty-first  operation  is  stamping  with  hand  stamps, 
the  work  being  held  in  a  fixture  while  this  operation  is  being 
performed.  Sixteen  stamps  are  necessary  and  the  produc- 
tion is  295  shells  in  ten  hours.  The  twenty-second  opera- 
tion is  re-tapping  the  hole  in  the  nose  of  the  shell  with  a 
Murchey  tap,  the  shell  being  held  in  an  Acme  single-head 
threading  machine,  carrying  a  chuck  instead  of  a  die-head. 
The  production  is  twenty-five  per  hour. 

The  twenty-third  operation  is  screwing  in  the  brass  nose 


MACHINING  HOWITZER  SHELLS  135 

bushing  by  hand,  holding  the  shell  in  a  fixture.  The  twen- 
ty-fourth consists  in  turning  the  brass  socket  in  a  McDou- 
gal,  20-inch,  engine  lathe,  one  cutting  tool  being  used;  the 
production  is  twenty  per  hour.  The  twenty-fifth  operation 
is  cleaning  out  the  shell  with  benzine  and  then  varnishing 
it  with  a  brush.  The  shell  is  laid  down  on  the  bench,  rolled 
back  and  forth  by  the  operator,  and  the  interior  varnished 
with  a  brush  shaped  like  a  large  toothbrush.  Two  men 
are  employed  for  this  operation  and  the  production  is  400 
in  ten  hours.  The  twenty-sixth  operation  is  baking  the 


Fig.  102.     Turning  Copper  Driving  Band 

varnish  on  the  shell  in  an  oven,  which  is  heated  to  300  de- 
grees F.  (about  150  degrees  C.).  This  oven  is  kept  at  a 
constant  temperature  and  the  shells  are  left  in  for  eight 
hours.  They  are  then  taken  out  and  allowed  to  cool  in  the 
air.  As  the  furnace  holds  240  shells,  the  production  is  240 
in  eight  hours. 

Pressing  on  and  Turning  Copper  Bands.  —  The  twenty- 
seventh  operation  is  pressing  on  the  copper  band,  which  is 
done  in  a  special  banding  machine  having  four  hydraulic 
cylinders.  The  production  is  225  in  ten  hours.  Turning 


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136 


MACHINING   HOWITZER  SHELLS 


137 


the  copper  band  is  the  twenty-eighth  operation ;  this  is  done 
in  a  Walcott  &  Wood,  22-inch,  engine  lathe,  equipped  with 
a  Lymburner  Ltd.  band  turning  attachment,  as  shown  in 


Fig.   104.     First   Machining  Operation  on    British  9.2-inch   High- 
explosive   Shell    Forging— drilling    Hole    in    Nose   and   facing 

Fig.  102.  This  attachment  carries  two  forming  tools,  one 
on  the  front  and  one  on  the  rear  of  the  cross-slide.  The 
operations  performed  are :  Rough-turn  band  with  a  tool  on 
the  top  of  the  slide,  operated  by  a  turnstile  at  the  front; 


138  MACHINING   HOWITZER  SHELLS 

rough-form  band  to  shape  with  a  form  tool;  and  finish 
band  with  a  forming  tool  held  on  a  special  attachment  at  the 
rear  of  the  machine  and  operated  by  a  separate  handle. 
The  work  is  rotated  at  250  R.  P.  M.  and  the  production  is 
twenty-five  per  hour. 

The  twenty-ninth  operation  is  the  final  inspection.  The 
thirtieth,  applying  the  first  coat  of  paint,  the  base  of  which 
is  white  lead;  the  thirty-first,  applying  the  second  coat  of 
yellow  paint.  After  drying,  the  shells  are  again  inspected 
and  packed  ready  for  shipment,  the  plug,  of  course,  being 
screwed  into  the  nose  to  prevent  foreign  matter  from  getting 
into  the  cavity  of  the  shell,  and  also  to  protect  the  threads 
in  the  nose  from  bruises.  The  plug  is  retained  in  the  shell 
until  it  is  removed  for  loading;  it  is  then  replaced  and  not 
removed  again  until  the  shell  reaches  the  field  of  operations, 
where  it  is  taken  out  and  the  detonating  fuse  substituted. 

Machining  9.2-inch  British  Howitzer  Shells.  —  Starting 
with  the  finished  forging,  which  is  made  with  a  closed-in 
nose  and  has  been  carefully  annealed,  the  first  machining 
operation  on  the  9.2-inch  British,  howitzer,  high-explosive 
shell  shown  in  Fig.  103  consists  in  drilling  a  two-inch  hole 
through  the  nose  and  in  facing  off  the  nose  end  of  the  shell 
until  the  required  length  is  obtained.  These  operations  are 
performed  on  a  six-foot,  radial,  drilling  machine,  as  shown 
in  Fig.  104,  using  a  two-station  jig  that  enables  one  side 
to  be  loaded  while  the  machining  operations  are  being  per- 
formed on  a  forging  located  on  the  other  side.  The  jig 
A  is  in  the  form  of  an  angle-plate,  and  the  radial  arm  of 
the  machine  is  moved  to  bring  the  tool  in  line  with  the 
work.  The  drilling  is  done  at  a  cutting  speed  of  from  60 
to  65  feet  per  minute  with  a  down  feed  of  1/64  inch  per 
revolution.  The  production  is  five  and  one-half  shells  per 
hour,  one  man  operating  the  machine. 

Cutting-off  and  Rough-turning  Operations.  —  The  next 
operation  is  cutting  off  the  open  end,  which  is  done  on  a 
Pond  24-inch  lathe.  The  forging  is  held  in  a  "pot-chuck" 
(see  Fig.  106),  and  is  gaged  from  the  end  just  machined. 
The  surplus  stock  on  the  open  end  is  cut  off  by  means  of  a 
special  carriage  carrying  two  cutting-off  tools,  and  oper- 


MACHINING   HOWITZER  SHELLS 


139 


ated  by  right-  and  left-hand  screws,  so  that  both  tools  are 
at  work  at  the  same  time.  The  blades  of  the  cutting-off 
tool  are  %  inch  wide,  and  the  surface  speed  of  the  work  is 
from  70  to  80  feet  per  minute.  One  man  operates  two  ma- 
chines and  cuts  off  seven  shells  per  hour. 

After  cutting  off,  the  straight  portion  of  the  shell  is 
rough-turned.  For  this  operation  the  shell  is  held  on  a 
mandrel  that  has  two  sets  of  expanding  plungers  and  the 
work  is  done  on  a  Pond  24-inch  lathe.  Two  cutting  tools 
are  used  and  remove  a  total  of  %  inch  on  the  diameter  in 


Fig.  105.     Turning  Radius  on  Nose  on  a  24-inch  Engine  Lathe 

one  cut.  Each  tool  removes  %  inch,  and  works  at  a  cut- 
ting speed  of  from  70  to  80  surface  feet  per  minute.  As  the 
forcings  vary  somewhat,  it  is  often  necessary  to  take  two 
cuts  to  finish.  The  longitudinal  feed  is  y8  inch  per  revolu- 
tion of  the  work.  At  this  setting,  the  nose  of  the  shell  is 
not  touched ;  the  next  operation  is  the  roughing  of  the 
nose  to  the  required  radius  on  a  Pond  24-inch  lathe,  Fig. 
105.  The  shell  is  gripped  from  the  internal  diameter  by  ex- 
panding mandrel  A,  fastened  to  the  faceplate  as  shown. 


140 


MACHINING   HOWITZER   SHELLS 


Two  cutting  tools  are  used  which  are  guided  in  the  cor- 
rect path  by  a  simple  but  satisfactory  device.  This  radius 
device  comprises  a  special  carriage  B  that  is  carried  on  a 
bracket  C  bolted  to  the  bed  at  the  rear  of  the  lathe.  Lo- 
cated on  carriage  B  is  a  stationary  slide  D  to  which  is 
bolted  a  link  E  that  serves  to  connect  the  cross-slide  F  with 
the  rear  carriage.  The  cross-feed  screw  ordinarily  used  is 
removed  so  that  the  motion  of  the  slide  F  in  a  radial  direc- 
tion is  controlled  by  the  link  E.  In  operation,  as  the  front 
carriage  is  fed  toward  the  faceplate,  the  link  E  forces  the 


Fig.  106. 


Rough-  and  finish-boring  Internal  Diameter  on  a  36-inch 
Engine  Lathe 


cross-slide  F  back  and  thus  guides  the  cutting  tools  in  a 
curved  path.  The  correct  starting  and  finishing  points  of 
the  radius  on  the  shell  are  obtained  by  adjusting  the  screw 
G.  The  production  for  rough-turning  the  straight  diameter 
and  nose  is  one  shell  per  hour. 

Boring,  Counterboring,  Facing,  and  Threading  Operations. 
—  The  boring  is  performed  on  a  Pond,  36-inch,  heavy-duty 
lathe  provided  with  a  rack  tailstock,  as  shown  in  Fig.  106. 
For  machining,  the  shell  is  held  in  a  "pot-chuck"  clamped 
to  the  faceplate  and  is  additionally  supported  by  a  steady- 
rest  as  shown.  The  interior  of  this  chuck  is  made  an 


MACHINING  HOWITZER  SHELLS  141 

easy  fit  for  the  shell,  which  is  held  by  contracting  the  split 
chuck  by  clamping  bolts  as  shown.  Two  three-tooth  boring 
reamers  are  used,  one  roughing  and  one  finishing,  which  re- 
move about  y%  inch  from  the  diameter  between  them.  The 
roughing  reamer  is  provided  with  high-speed  steel  blades 
which  are  serrated  to  break  up  the  chip,  whereas  the  finish- 
ing reamer  is  provided  with  smooth  blades  of  high-speed 
steel.  The  cutting  speed  of  the  reamers  is  from  74  to  78 
surface  feet  per  minute.  The  longitudinal  feed  is  very 
coarse  (1/2  inch  per  revolution)  until  the  radius  is  reached, 


Fig.  107.     Set-up  on  a  24-inch  Engine  Lathe  for  machining  Band 
Groove  and  cutting  Wave  Ribs 

where  it  is  reduced  to  1/32  inch  per  revolution.     The  pro- 
duction is  one  shell  per  hour. 

Following  the  operation  just  described,  a  series  of  opera- 
tions is  performed  on  the  nose  of  the  shell  on  a  Pond  24-inch 
lathe  provided  with  a  four-sided  turret.  The  shell  is  held  in 
a  pot-chuck,  but  with  the  nose  instead  of  the  base  end  pro- 
jecting. The  operations  are :  Rough- and  finish-bore  open- 
ing, rough-face  end,  tap  and  finish-face  end.  The  finishing 
cuts  are  taken  at  an  average  speed  of  120  surface  feet  per 
minute  and  the  feed  is  1/32  inch  per  revolution.  The  pro- 
duction is  two  shells  per  hour. 


142 


MACHINING    HOWITZER    SHELLS 


The  reverse  end  of  the  shell  is  now  machined,  and,  as  in 
the  previous  operation,  is  held  in  a  pot-chuck.  The  work 
is  done  on  a  Pond  24-inch  lathe  provided  with  a  four-sided 
turret.  The  operations  are:  Face  off  base  end,  bore  and 
counterbore,  and  chase  thread  for  base  plug.  The  cutting 
speeds  are  120  surface  feet,  feeds  1/32  inch  per  revolution, 
and  production,  one  shell  per  hour. 

Finish-turning,  Grooving,  Waving,  and  Assembling  Base 
Plug.  —  The  finish-turning  on  the  external  diameter  is  done 
on  a  Pond  24-inch  lathe  provided  with  a  former  plate,  some- 
what similar  in  design  to  an  ordinary  taper-turning  attach- 
ment. One  cutting  tool  is  used  and  one  cut  finishes  the 
work.  The  speed  is  120  surface  feet,  and  the  feed  1/32 
inch  per  revolution.  The  production  is  two  shells  in  three 
hours. 


DRIVE 
a      \^_ 

1  C 

UJ 

°\F 

jo 

La 

{   F 

?OM  FACEPLATE 

~~--.,. 

--^          \x           CENTER 

""""!'  thi^ 

j;  [PjL  n 

- 

Machinery 

Fig.    108.     Diagram    showing    Details   of   Construction    of    Mandrel 
used  for  holding  Shell  when  performing  Operation  shown  in  Fig.  107 

The  shells  are  then  taken  to  the  Pond  24-inch  lathe 
shown  in  Fig.  107,  where  the  band  groove  is  cut  and  the 
wave  ribs  produced.  The  shell  is  held  on  a  special  mandrel 
A  (see  Fig.  108  for  details  of  construction)  which  is  driven 
by  a  special  faceplate  B,  Fig.  107,  that  carries  the  cam  C 
used  in  oscillating  the  rear  waving  slide  D.  The  lathe  car- 
riage is  provided  with  a  turret  toolpost  E  carrying  four 
tools  that  perform  the  following  operations :  Tools  F  neck 
at  the  limits  of  the  band  groove,  tool  G  roughs  out  the 
groove  to  the  top  of  the  ribs,  tool  H  under-cuts  the  edges 
of  the  groove,  and  tool  /  roughs  out  between  the  wave 
ribs.  The  wave  ribs  are  produced  by  the  special  fixture  D 
held  on  the  rear  of  the  carriage.  This  comprises  a  slide  J 
which  is  oscillated  by  the  cam  C  against  the  tension  of  a 


MACHINING  HOWITZER  SHELLS 


143 


spring  K,  and  carries  a  tool-holder  L  that  holds  the  waving 
tool  M.  Tool-holder  L  is  adjusted  for  position  by  screw  N. 
This  fixture  is  operated  by  bringing  the  cross-slide  forward 
and  moving  the  carriage  over  until  a  roll  (not  shown)  en- 
gages with  the  cam  C  that  imparts  the  required  oscillat- 
ing movement  to  slide  /.  The  band  grooves  are  cut  and 
ribbed  at  the  rate  of  eighteen  shells  in  ten  hours.  The 
base  plug  and  nose  bushing  are  put  in  by  hand.  Each  plug 
is  carefully  fitted  and  cleaned,  and  is  left  partly  screwed 
in  place  until  such  time  as  the  loading  of  the  shell  is  fin- 
ished. 


Fig.  109.     Set-up  for  turning  Copper  Band  to  Shape  on  a  24-inch 
Engine  Lathe 

Banding  and  Band-turning  Operations.  —  The  pressing  on 
of  the  copper  driving  band  is  performed  in  a  Dudgeon  hy- 
draulic banding  press.  The  copper  bands  are  heated  to  a 
bright  red  in  a  "Best"  oil  furnace,  and  when  they  have  at- 
tained the  correct  temperature  they  are  quickly  removed  and 
placed  in  the  banding  press.  The  shell  is  then  placed  in  the 
press,  the  band  being  slipped  over  it  and  located  by  the  dies 
in  the  correct  relation  to  the  groove.  As  the  press  is  operated, 
six  dies  are  forced  in  radially  and  compress  the  band  into 
the  groove.  After  the  first  squeeze,  the  shell  is  turned  30 
degrees  and  given  another  squeeze.  The  production  on  this 
operation  is  about  twenty  shells  per  hour. 


144 


MACHINING  HOWITZER  SHELLS 


The  copper  band  is  turned  on  the  Pond  24-inch  lathe 
shown  in  Fig.  109.  Here  it  is  supported  and  driven  from 
one  end  by  a  special  driver  A,  Fig.  110,  and  is  supported 
on  the  nose  end  by  a  revolving  center  B.  The  cross-slide 
carries  a  turret  toolpost  A,  Fig.  109,  holding  four  tools, 
which,  in  conjunction  with  a  forming  tool  on  the  rear  of 
the  slide,  rough-  and  finish-turn  the  band  to  shape.  The 
production  is  three  shells  per  hour. 

Weighing,  Cleaning,  Varnishing,  etc.  —  Upon  the  comple- 
tion of  the  machining  operations,  the  shells  are  weighed, 
the  limit  in  weight  being  10  ounces  either  way  from  the 
standard,  which  is  252  pounds.  Working  from  the  nose 


\DRIVI!NG  PIN 


OMBINED  DRIVER  AND  CENTERING  CHUCK 


REVOLVING  CENTER 


Machinery 


Fig.   110.     Diagram   showing    Method   of   holding   and   driving   Shell 
when   performing  Operation  shown   in   Fig.   109 

end,  the  shell  is  now  washed  out  with  soda  water  and  then 
dried,  after  which  a  coating  of  Copal  varnish  is  sprayed 
in  with  a  Buffalo  air-spray  brush.  The  shell  is  swabbed 
outside,  while  hot,  with  a  light  machine  oil  and  then  baked 
for  eight  hours  at  a  temperature  of  300  degrees  F.  (about 
150  degrees  C.). 

Because  of  their  weight,  these  shells  are  too  heavy  to 
handle  by  hand,  so  light  air  hoists  are  located  over  each 
machine  to  facilitate  handling.  These  hoists  travel  on  a 
continuous  track,  which  runs  down  the  aisle  of  the  shop  be- 
tween two  rows  of  machines  along  which  the  shells  are  kept 
moving.  Stamping,  inspecting,  etc.  finish  the  operations  on 
the  shell,  after  which  it  is  ready  for  packing  and  boxing. 


CHAPTER  VIII 

MISCELLANEOUS  TOOLS  AND  DEVICES  FOR  SHELL 
MANUFACTURE 

BRITISH,  18-pound,  high-explosive  shells  are  made  from 
bar  stock,  the  usual  method  being  to  rough  out  the  hole 
in  a  high-power  drilling  machine.  Figs.  Ill  and  112  show 
an  efficient  method  of  accomplishing  this  operation.  The 
machines  used  are  Baker  Nos.  310  and  315,  vertical,  high- 
power,  drilling  machines  (the  latter  size  being  of  the  extra- 
heavy  pattern)  equipped  with  a  special  fixture  a  clamped 
to  the  table.  This  fixture  is  provided  with  four  tool-steel 
holding  jaws  that  support  the  bar  in  a  vertical  position,  and 
are  operated  by  right-  and  left-hand  screws  by  means  of  a 
turnstile  b.  At  A,  Fig.  Ill,  is  shown  the  first  rough-drilling 
operation,  which  is  accomplished  by  means  of  a  1  13/16-inch 
diameter  high-speed  drill  driven  at  175  R.  P.  M.  with  a  down 
feed  of  0.020  inch  per  revolution.  The  drilling  time  is  about 
three  minutes  per  shell;  B  shows  the  second  operation, 
which  consists  in  removing  the  vee  left  by  the  point  of  the 
drill,  and  rounding  the  bottom ;  and  C  shows  the  final  ream- 
ing operation.  In  Fig.  112,  D  illustrates  the  special  tool 
used  for  machining  the  exterior  of  the  nose  of  the  shell. 
This  tool  is  designed  along  the  principles  of  a  hollow-mill 
carrying  one  inserted  high-speed  steel  blade.  In  this  set- 
up, a  special  bushed  bracket  is  fastened  to  the  top  of  the 
fixture,  to  support  the  large  nose  turning  tool. 

Previous  to  cutting  the  thread  in  the  nose  of  the  shell,  it 
is  necessary  to  recess  it  at  the  point  where  the  thread  ter- 
minates, as  shown  at  E.  This  is  accomplished  by  a  recess- 
ing tool  of  the  construction  shown  in  Fig.  113.  This  tool 
consists  of  a  holder  A  provided  with  a  tang  fitting  into  the 
drilling-machine  spindle.  This  carries  a  sleeve  B  that  is 

145 


146 


147 


148 


MISCELLANEOUS  TOOLS 


operated  upon  by  a  spring  C,  lying  between  the  recessed 
shoulder  of  the  sleeve  and  a  washer  D  that  is  pinned  to  the 
bar  A.  The  recessing  tool  proper  E  is  carried  in  an  elon- 
gated slot  in  the  lower  end  of  the  bar  A  and  is  operated 
by  means  of  an  angular  slot  in  the  bar  through  a  pin  driven 
through  the  recessing  tool.  In  operation,  the  drilling-machine 
spindle  is  brought  down  until  the  sleeve  B  contacts  with  the 
nose  of  the  shell,  whereupon,  further  downward  movement 
of  the  spindle  compresses  spring  C  and  at  the  same  time 
forces  out  the  recessing  tool  E,  cutting  an  annular  groove 
in  the  interior  of  the  nose.  The  last  operation,  as  per- 
formed in  the  drilling  machine,  consists  in  threading,  and 


Machinery 


Fig.   113. 


Special   Recessing  Tool   used  for  performing  Operation 
E    shown    in    Fig.    112 


it  is  accomplished  with  a  collapsible  tap  as  illustrated  at  F, 
Fig.  112. 

The  lay-out  advocated  by  Baker  Bros,  for  this  work  is  a 
gang  of  six  machines,  consisting  of  two  No.  315  extra- 
heavy  pattern  machines  for  the  drilling  and  nose-turning 
operations,  and  four  No.  310  machines  for  the  bottoming, 
reaming,  counterboring,  facing,  under-cutting,  and  tapping 
operations.  This  gang  of  six  machines  gives  a  production 
of  eight  shells  per  hour,  and  leaves  them  ready  for  the  lathe- 
turning  operations. 

Surfacing  Gas  Plugs  on  Besly  Ring-wheel' Grinders. — 
The  gas  plug  used  in  the  base  end  of  British  high-explosive 
shells  is  made  from  a  forging  and  must  be  faced  on  the  end 
that  is  next  to  the  shell.  Several  methods  are  used  in  sur- 


MISCELLANEOUS  TOOLS 


149 


facing  the  inner  face  of  this  plug;  a  very  satisfactory  one 
is  to  grind  it  on  a  Besly,  No.  14-16,  wet,  ring- wheel  grinder, 
shown  in  Fig.  114,  which  is  equipped  with  a  special  rotary 
chuck,  shown  in  detail  in  Fig.  115.  Fig.  114  shows  two 
operators  at  work  grinding  the  face  of  gas  plugs.  The 
jaws  of  this  rotary  chuck  are  threaded  to  grip  the  threaded 
body  of  the  plug  when  the  latter  is  machined ;  consequently, 
the  base  is  finished  true  with  the  threaded  body  of  the  plug. 
For  grinding,  a  cylinder  type  of  wheel  is  held  in  the  stand- 
ard, Besly,  pressed-steel,  ring-wheel  chuck.  The  wheel  is 


Fig.  114.     Surfacing  High-explosive  Shell  Gas  Plugs  on  a  Besly  No.  14-16-inch 
L  "Wet"   Ring-wheel   Grinder 

about  16  inches  in  diameter,  3  inches  face.  Gas  plugs  for 
British  4.5-inch  high-explosive  shells  can  be  turned  out 
from  the  rough  at  the  rate  of  from  sixty  to  eighty  per  hour 
for  one  operator  by  this  machine.  The  machine,  of  course,  is 
double-ended,  so  that  two  operators  can  work  on  one  ma- 
chine at  the  same  time.  The  action  of  the  grinding  wheel 
rotates  the  work  while  grinding,  producing  the  desired 
accuracy. 

The  Besly  grinder  shown  in  Fig.  114  is  also  used  for 
grinding  off  the  projections  on  gas  plugs  and  facing  the 


150 


MISCELLANEOUS   TOOLS 


base  end.  On  the  British,  18-pound,  high-explosive  shell, 
the  projection  on  the  end  of  the  gas  plug  is  about  %  inch 
long  and  %  incn  *n  diameter,  of  square  section.  (In  some 
cases  this  section  is  made  triangular  in  shape.)  On  the 


Fig.  115.     Special   Rotary  Chuck  used  on   Besly  Disk  Grinder  for 
surfacing  Gas  Plugs 


Fig.    116.     Three-Inch    High-explosive    Shell,    showing    Finish    left 
by  Besly  Grinder;  also  Two  Types  of  Gas  Plugs 

Besly  grinder,  twenty-five  shells  can  be  ground  per  hour. 
The  grinding  machine,  of  course,  accommodates  two  opera- 
tors, giving  a  combined  production  of  fifty  shells  per  hour 
per  machine.  At  the  same  time  that  the  projection  is  re- 
moved from  the  gas  plug,  the  surface  of  the  gas  plug  is 


MISCELLANEOUS   TOOLS 


151 


also  ground,  1/32  inch  of  material  being  removed.  The 
diameter  of  the  plug  on  the  18-pound  shell  is  about  2^4 
inches,  as  shown  in  Fig.  116.  Where  the  projection  on 
the  gas  plug  is  triangular  in  shape,  the  production  can  be 


Fig.  117.     Testing   Hardness  of   High-explosive  Shells  with  Sclero- 

scope 

greatly  increased  because  this  projection  is  only  %  instead 
of  %  inch  high.  On  the  type  of  gas  plug  here  described, 
the  production  is  about  100  shells  per  hour  per  operator, 
or  200  shells  per  machine.  Fig.  116  shows  a  British  high- 
explosive  shell  that  has  been  finished  off  on  the  base  on  the 


152  MISCELLANEOUS  TOOLS 

Besly  grinder  illustrated  in  Fig.  114  and  also  the  two  types 
of  gas  plugs  referred  to.  The  one  shown  at  A  is  of  trian- 
gular section,  whereas  the  one  shown  at  B  is  of  square  sec- 
tion with  a  hole  in  the  center. 

Testing  Hardness  of  High-explosive  Shells.  —  When  or- 
ders for  high-explosive  and  shrapnel  shells  were  first  placed 
in  the  United  States  and  Canada,  considerable  trouble  was 
experienced  in  getting  shells  to  pass  the  government  in- 
spectors. While  a  large  number  of  concerns  were  success- 
ful in  getting  the  shells  finished  to  the  required  dimensions, 
many  experienced  trouble  in  heat-treating  shrapnel  shells 
and  attaining  the  desired  physical  properties.  The  govern- 
ment inspectors  finally  decided  on  using  testing  apparatus 
that  could  be  applied  to  every  shell  after  heat-treatment 
and  thus  check  up  the  tensile  strength  of  the  shells.  There 
are  two  well-known  methods  of  testing  the  hardness  of 
metals,  the  Shore  and  the  Brinell.  The  Brinell  is  the  older 
and  uses  the  instrument  shown  in  Fig.  81;  the  Shore 
makes  use  of  the  scleroscope  shown  in  Fig.  117.  The 
British  government  has  been  using  both  of  these  methods 
for  some  time,  but,  in  general,  on  shell  work,  the  Shore 
method  has  been  adopted  because  of  the  rapidity  with  which 
the  test  could  be  made.  Also  it  did  not  injure  the  parts 
and  could  be  used  on  hardened  metal,  for  which  the  Brinell 
method  is  not  as  adaptable. 

Extensive  tests  have  shown  that  there  is  very  little  dif- 
ference in  the  results  obtained  with  these  methods.  What 
little  difference  there  is,  is  due  principally  to  the  Brinell 
indenting  pressure,  which  is  applied  slowly  and  then  left 
on  for  fifteen  seconds  or  more.  The  time  taken  and  the 
extreme  stress  imposed  causes  undue  variation  depending 
on  the  ductility  of  the  metal.  In  fact,  the  Brinell  reading 
is  so  influenced  by  ductility  that  claims  have  been  made 
that  it  shows  the  ultimate  strength;  as  a  matter  of  fact, 
however,  the  reading  taken  by  the  Brinell  method  is  an 
expression  of  the  elastic  limit.  The  scleroscope,  on  the 
other  hand,  imposes  on  the  metal  an  instantaneous  limited 
stress,  and  thus  causes  only  slight  mechanical  super-hard- 
ening, so  it  logically  preserves  the  original  values  and  serves 


MISCELLANEOUS  TOOLS  153 

to  indicate  the  elastic  limit  without  undue  variation  leaning 
toward  the  ultimate  strength.  It  is  for  this  reason  that 
exact  comparison  between  the  two  tests  can  only  be  made 
on  one  kind  of  metal  at  a  time  or  in  a  given  state  of  heat- 
treatment.  On  heat-treated  steel  used  in  shrapnel  and  high- 
explosive  shells,  the  ratio  is  given  by  Shore  as  6.4,  meaning 
that  if  the  scleroscope  shows,  for  example,  50  hard,  this 
multiplied  by  6.4  would  give  the  Brinell  hardness,  or  a  value 
of  320. 

Hardness  of  High-explosive  Shells.  --The  shells  used  by 
the  British  government  are  made  from  a  special  tough  alloy 
steel,  the  required  physical  properties  of  which  are  con- 
tained in  the  "raw"  steel,  so  that  it  does  not  require  to  be 
heat-treated  after  machining.  Their  specifications  are : 

Per  Cent 

Constituents  Min.  Max. 

Carbon 0.55 

Nickel 0.50 

Silicon 0.30 

Manganese   0.4  1.00 

Sulphur 0.04 

Phosphorus   0.04 

Copper 0.10 

This  steel  in  an  untreated  condition  must  give  a  yield  point 
of  19  tons  and  a  breaking  strength  of  from  35  to  49  tons, 
with  an  elongation  of  from  17  to  20  per  cent.  The  scleros- 
cope is  used  to  test  each  bar  of  stock  after  the  first  external 
cut  or  before  any  of  the  important  machining  operations 
have  been  performed,  so  that  any  defects  in  the  material 
can  be  discovered  before  it  has  gone  too  far. 

The  French  high-explosive  shell  is  made  from  steel  con- 
taining a  lower  percentage  of  carbon  and  no  nickel.  The 
specifications  on  the  French  high-explosive  shell  are : 

Per  Cent 

Constituents  Min.  Max. 

Carbon    0.30  

Silicon 0.18  

Manganese 0.50  0.80 

Phosphorus   0.04  0.07 

Sulphur 0.05 


154  MISCELLANEOUS  TOOLS 

After  hardening  and  tempering,  a  tensile  strength  of 
125,170  pounds  per  square  inch  is  required  with  an  18.3 
per  cent  elongation.  The  elastic  limit  would  be  about 
from  80,000  to  120,000  pounds  per  square  inch,  or  as  shown 
in  Fig.  117,  from  43  to  52  hardness  on  the  scleroscope  and 
from  275  to  333  on  the  Brinell  instrument,  respectively. 
The  elongation  and  ultimate  strength  are  determined  by- 
testing  a  shell,  selected  at  random,  to  destruction. 

The  Russian  high-explosive  shell  has  a  chemical  composi- 


Fig.  118.     Ford-Smith   Plain   Wide  Wheel   Shell   Grinder 

tion  somewhat  similar  to  the  French.  It  is  hardened  and 
tempered  to  show  a  physical  property  giving  an  elastic 
limit  of  not  less  than  62,000  pounds  per  square  inch,  a  ten- 
sile strength  of  118,000  pounds  per  square  inch,  and  an 
elongation  of  10  per  cent.  These  properties  in  a  steel  of 
the  chemical  constitutents  just  given  would  give  a  sclero- 
scope hardness  of  from  40  to  45  when  heat-treated. 

Grinding  High-explosive  Shells.  —  The    British    high-ex- 
plosive shell  is  not  heat-treated,  and,  consequently,  many 


MISCELLANEOUS  TOOLS 


155 


manufacturers  are  finishing  the  external  diameter  to  size 
and  shape  by  turning ;  others,  however,  are  using  the  grind- 
ing method.  The  turning  method  cannot  be  used  as  suc- 
cessfully on  the  Russian  or  French  shells,  because  these  are 
heat-treated.  The  practice  followed  in  grinding  high-ex- 
plosive shells  differs  in  various  plants.  The  diagrams,  Figs. 


Machinery 


Fig.  119.  Diagram  Illustrating  Methods  of  finishing  High-explosive 
Shell  Bodies  by  turning  and  grinding 

119  and  120,  show  several  methods  that  are  employed  in 
grinding  high-explosive  shells  on  the  Ford-Smith  heavy- 
type,  plain  grinder  shown  in  Fig.  118.  Considerable  im- 
provements have  been  made  in  grinding  high-explosive 
shells,  especially  as  regards  keeping  the  face  of  the  wheel 
true.  When  this  method  was  adopted,  it  was  thought  that 


156 


MISCELLANEOUS  TOOLS 


it  would  be  necessary  to  true  up  the  face  of  the  wheel  with 
a  diamond  truing  device  after  grinding  a  comparatively 
small  number  of  shells.  This,  however,  has  not  proved  to 
be  the  case,  and  the  truing  up  of  the  face  of  the  wheel  can 
be  done  quickly  by  hand  by  the  use  of  a  carborundum  stick. 
A  comparatively  large  number  of  shells  can  be  turned  out 


Machinery 


Fig.  120. 


Diagram  illustrating  Method  of  finishing  High-explosive 
Shells  by  grinding 


with  one  truing  of  the  wheel,  and  on  the  Ford-Smith  ma- 
chine a  special  wheel-truing  device,  as  illustrated  in  Fig. 
121,  is  used. 

The  diagram  in  Fig.  119  illustrates  three  methods  of 
grinding  high-explosive  shells  of  the  18-pound  size.  That 
shown  at  A  consists  in  finishing  the  nose  of  the  shell  on  the 


MISCELLANEOUS   TOOLS 


157 


lathe,  and  then  grinding  the  external  diameter  from  the 
band  groove  to  the  radius,  with  a  two-inch  face  wheel,  by 
traversing  the  work  past  the  wheel.  In  the  method  shown 
at  B,  a  six-inch  face  wheel  is  used ;  this  finishes  the  entire 
body  of  the  shell,  except  the  nose,  which  is  turned  in  the 
lathe  in  one  straight-in  cut.  The  method  shown  at  C  is 
that  employed  on  the  Ford-Smith  grinder  in  British  plants. 
The  nose  is  turned  in  the  lathe  and  the  body  is  ground  with 
a  wide  wheel,  generally  about  8i/2  inches.  The  grinding  is 
done  completely  across  the  shell,  the  band  groove  being 
cut  in  a  subsequent  operation.  The  production  obtained  on 


Fig.   121.     Wheel-truing   Device  used  on   Ford-Smith   Grinding 
Machine 

the  18-pound  shell  when  these  various  methods  are  used 
differs  considerably.  When  using  the  method  shown  at  A, 
the  production  is  about  from  fifteen  to  twenty  per  hour ;  by 
method  B,  from  twenty  to  thirty  per  hour ;  and  by  method  C, 
from  twenty-five  to  thirty  per  hour. 

Fig.  120  shows  methods  of  finishing  high-explosive  shell 
bodies  by  grinding  all  over;  A  and  B  show  two  methods 
of  finishing  high-explosive  shells  on  a  plain  grinder.  The 
procedure  followed  varies.  In  some  cases,  the  body  is  fin- 
ished first  and  the  nose  later,  whereas,  in  others,  the  nose, 
as  shown  at  A,  is  ground  first  and  then  the  body,  as  shown 


158 


MISCELLANEOUS  TOOLS 


at  B.  The  method  that  is  shown  at  C  is  being  used  in 
Canada  at  the  present  time.  In  this  method,  wheels  as 
wide  as  lli/^  inches  face  have  been  used,  covering  the  en- 


Fig.   122. 


Machine    built   by   Spray    Engineering    Co.   for  spraying 
Interior  of  High-explosive  Shells 


tire  length  of  the  shell.  On  the  18-pound  shell,  the  produc- 
tion varies  from  twenty  to  twenty-five  per  hour,  whereas 
on  the  4.5  shell,  using  an  11^-inch  face  wheel,  the  produc- 
tion is  somewhat  less. 


MISCELLANEOUS  TOOLS  159 

The  special  wheel-truing  device  used  on  the  Ford-Smith 
plain  grinder,  shown  in  Fig.  118,  is  illustrated  in  Fig.  121. 
This  device  is  held  on  swinging  arm  bracket  A,  fulcrumed 
on  pin  B,  and  located,  when  in  position  to  true  the  face  of 
the  wheel,  by  stud  C.  The  holder  D,  carrying  the  diamond 
tool,  is  provided  at  its  rear  end  with  a  hardened  cam  sur- 
face that  is  kept  in  contact  with  the  forming  cam  E  by 
means  of  a  spring  located  in  the  body  of  the  attachment. 
The  method  of  operating  this  device  is  as  follows :  After 
swinging  the  attachment  into  position  and  locking  it,  the 
wheel  slide  is  advanced  until  the  diamond  contacts  with  the 
wheel ;  crank  handle  F  is  then  rotated.  This  carries  a  gear 
that  meshes  with  another  gear  in  the  enclosed  case  G.  The 
stud  in  this  case  extends  down  through  the  fixture  and 
engages  another  gear  operating  in  a  rack.  Consequently, 
the  turning  of  this  handle  moves  slide  H  back  and  forth, 
and  traverses  the  diamond  holder  past  the  face  of  the  wheel. 
This  diamond  truing  device  is  only  used  occasionally  to 
bring  the  wheel  to  the  correct  shape  and  to  dress  up  new 
wheels;  for  slight  dressing,  a  carborundum  stick  is  used. 

Varnishing  Interior  of  High-explosive  Shells.  —  In  Fig.  122 
is  shown  a  machine  built  by  the  Spray  Engineering  Co., 
Boston,  Mass.,  provided  with  an  apparatus  for  spraying 
the  necessary  protective  coating  on  the  inside  of  a  high- 
explosive  shell.  The  machine  comprises  a  table  with  steel 
supporting  frames,  and  has  the  operating  mechanism  placed 
beneath  it.  The  coating  material,  such  as  varnish,  as- 
phaltum  paint,  and  similar  compounds,  is  carried  in  a  tank 
located  above  the  operating  table,  and  passes  down  the  hol- 
low tank  supports  to  an  adjustable  measuring  device  which 
controls  the  amount  of  material  sprayed  at  each  operation. 
A  system  of  levers  controls  the  motion  of  this  device,  cut- 
ting off  the  supply  from  the  tank  and  admitting  measured 
quantities  of  material  to  a  channel  leading  to  the  spraying 
nozzle.  The  last  part  of  this  motion  opens  a  connection  to 
a  compressed-air  supply,  which  drives  the  coating  material 
through  the  spray  nozzles  and  distributes  it  evenly  over  the 
surfaces  to  be  covered.  A  high  working  speed  is  thus  ob- 
tained without  waste  of  material  and  one  setting  of  the 


160  MISCELLANEOUS  TOOLS 

measuring  device  insures  delivery  of  a  fixed  quantity  of  the 
material  to  each  shell. 

To  operate  the  machine,  the  shell  is  inverted  over  the  hole 
in  the  operating  table.  A  slight  pressure  on  the  foot  lever 
connected  with  the  operating  lever  moves  the  measuring 
device  and  admits  compressed  air.  Upon  the  removal  of 
pressure  from  the  treadle,  suitable  coil  springs  return  the 
mechanism  to  its  oringinal  position,  ready  for  the  next 
operation.  A  particular  feature  of  the  machine  is  the  de- 
vice for  admitting  a  fixed  amount  of  coating  material  at 


Fig.  123.     Mathews  Gravity  Carrier  transporting  Shell   Forgings 

each  operation,  which  permits  setting  the  mechanism  to 
repeat  any  predetermined  coating  operation  on  a  large 
number  of  similar  parts.  For  readily  changing  over  to  dif- 
ferent coating  materials,  drain  valves  and  priming  valves 
permit  a  thorough  cleaning  of  the  measuring  device  and  all 
pipe  passages  without  taking  the  mechanism  apart.  The 
height  of  the  spray  head  may  be  adjusted  for  coating  shells 
of  various  dimensions,  and  auxiliary  attachments  including 
a  movable  spray  head  are  used  when  it  is  required  to  cover 
a  large  surface  or  to  meet  other  special  conditions. 


MISCELLANEOUS  TOOLS  161 

Conveying  Apparatus  for  Rapid  Handling  of  Shells. - 
For  conveying  shell  forgings  from  one  department  to  an- 
other or  from  the  shipping  department  to  freight  cars,  etc., 
the  Mathews  Gravity  Carrier  Co.  has  designed  conveying 
apparatus  as  shown  in  Figs.  123  and  124,  respectively.  Fig. 
123  shows  this  gravity  carrier  being  used  for  transporting 
forgings  from  a  freight  car  to  the  machining  department 
of  a  plant,  whereas  Fig.  124  shows  a  special  arrangement  of 
the  carrier  for  handling  shells  that  are  boxed  and  ready  for 
shipment.  In  this  case,  the  track  part,  which  extends  into 


Fig.    124.     Mathews    Gravity    Carrier   with    Elevator    Unit 
loading    Freight   Car 

the  shipping  room,  is  about  two  feet  above  the  floor  level 
and  the  inclined  elevator  arrangement  lifts  the  boxes  so  that 
they  are  located  in  the  car  four  feet  above  the  floor  level. 
The  idea  of  elevating  the  boxes  is  to  have  them  within  con- 
venient reach  of  the  shipper.  The  elevator  is  not  necessary 
where  the  floor  of  the  car  is  on  the  same  level  as  the  floor  of 
the  building. 

The  chief  advantage  of  this  conveying  apparatus  is  that  it 
is  easily  and  quickly  installed  and  is  built  up  of  separate 
units  so  that  it  can  be  added  to  without  any  extra  cost 
except  the  cost  for  extra  length  of  carriers  and  stands.  The 


162  MISCELLANEOUS  TOOLS 

rollers  are  made  from  seamless  cold-drawn  steel  tubing  and 
run  in  ball  bearings.  The  grade  of  the  apparatus  is  from 
2  to  3  per  cent.  Where  it  is  necessary  to  lift  the  shells  or 
other  parts  being  transported  from  a  floor  into  a  car,  a  por- 
table elevator  is  used  as  shown  in  Fig.  124.  This  elevator  is 
driven  by  a  one-horsepower  motor  and  can  be  connected  to . 
a  lamp  socket.  Another  application  of  this  system  is  where 
the  carrier  arrangement  comes  to  the  end  of  the  building  and 
it  is  necessary  to  return  the  work;  to  accomplish  this,  a 
double-deck  arrangement  is  provided,  the  lower  deck  inclin- 
ing one  way  and  the  upper  deck  the  other  way.  Thus 
when  the  shells  or  work  come  to  the  end  of  the  line,  they  are 
simply  placed  on  the  upper  deck  and  are  returned  to  the 
next  series  of  machining  operations,  without  any  handling 
whatsoever.  Another  advantage  of  this  system  is  that  the 
shells  or  work  do  not  need  to  touch  the  floor  at  all,  and,  con- 
sequently, expensive  cement  floors  are  not  broken  up  by  hav- 
ing heavy  work  dropped  on  them.  Lifting  the  work  off  the 
carrier  is  also  more  convenient  than  lifting  it  from  the  floor. 
The  important  feature  of  the  Mathews  gravity  roller  car- 
riers is  that  gravity  takes  the  place  of  other  power  con- 
veyors, except  where  additional  elevations  are  necessary 
or  where  shells,  forgings,  and  boxes  must  be  elevated  to 
upper  floors.  For  this  work,  the  Mathews  Gravity  Carrier 
Co.  makes  automatic-incline  or  straight-lift  elevators, 
which  require  only  a  very  small  motor. 


CHAPTER  IX 
BRITISH  HIGH-EXPLOSIVE  DETONATING  FUSE 

THE  British  high-explosive  shell  described  in  connection 
with  Fig.  3  carries  a  nose  fuse  of  the  concussion  type,  also 
shown  in  Fig.  9,  which  is  made  chiefly  from  brass  parts 
with  the  exception  of  the  adapter  B,  Fig.  125,  and  the 
gaine,  which  are  made  of  soft  steel.  The  body  of  the  fuse, 
shown  completely  machined  at  D,  Fig.  126,  and  at  C  and  D, 
Fig.  127,  is  first  cast  in  a  sand  mold  in  the  form  of  a  slug, 


Fig.  125. 


British  No.  100  Graze  High-explosive  Fuse  dismantled 
and  assembled 


as  shown  at  A,  Fig.  126.  The  composition  from  which  this 
slug  is  made  is  about  59.18  per  cent  copper,  39.45  per  cent 
zinc,  0.88  per  cent  manganese  copper  and  0.49  per  cent  phos- 
phor-copper, this  having  been  found  to  give  the  tensile 
strength  required  by  the  specifications  t 

The  first  operation  consists  in  snagging  and  brushing  the 
castings  with  a  wire  brush,  but  experiments  are  being  made 
to  force  the  casting  through  a  simple  die  that  shaves  off 

163 


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166  DETONATING  FUSES 

the  straight  surface  and  removes  all  objectionable  projec- 
tions. After  casting,  the  slugs  are  sand-blasted,  or  other- 
wise cleaned,  and  are  then  placed  in  the  Stewart  furnace 
shown  in  Fig.  128,  where  they  are  heated  to  1600  degrees 
F.  (about  870  degrees  C.).  The  ovens  of  these  Stewart 
gas  furnaces  are  double  ended,  and  a  Zeh  &  Hahnemann 
percussion  press,  Fig.  129,  is  located  at  one  end  of  the  fur- 
nace. Three  men  are  required  for  each  forging  press ;  one 
loads  the  furnace  from  the  rear,  another  takes  the  heated 
forgings  out  of  the  front  end  of  the  furnace,  puts  them  in 
the  die,  and  trips  the  press,  and  the  third  removes  them 
from  the  dies.  After  the  slugs  have  reached  a  temperature 
of  1600  degrees  F.,  they  are  removed  from  the  furnace  and 


^       ^   ^5i^ 


Fig.  126.     Sequence  of  Operations  on  Body  of  British  No.  100  Graze 
High-explosive   Fuse 

placed  in  the  dies  shown  in  Fig.  130,  and  in  Fig.  131  removed 
from  the  press.  The  furnace  shown  in  Fig.  128  holds 
forty-eight  slugs,  and  from  1400  to  1500  forgings  are  secured 
from  each  press  in  a  day  of  9%  hours.  The  ideal  forging 
obtained  from  the  dies  is  one  in  which  there  is  3/64  inch  of 
material  to  remove  all  around.  The  dies  shown  in  Figs. 
130  and  131  are  kept  flushed  with  a  compound  consisting 
of  64  per  cent  oil,  32  per  cent  water,  3  per  cent  powdered 
graphite,  and  1  per  cent  soda  ash.  The  order  in  which 
these  operations  are  accomplished,  as  well  as  the  machines 
used,  spindle  speeds,  and  the  production  obtained,  are  given 
in  Table  V. 

First  Machining  Operation  on  Fuse  Body. —  For  the  first 
machining  operation,  the  brass  body  is  held  in  an  air  chuck, 


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168  DETONATING  FUSES 

Second  Machining  Operation  on  Fuse  Body. —  The  second 
machining  operation  on  the  fuse  body  consists  in  finishing 
the  taper  end.  The  threaded  end,  as  shown  in  Fig.  133,  is 
gripped  in  an  air  chuck  and  the  following  operations  per- 
formed: Face  with  cross-slide  tool  G,  center  with  tool  A, 
drill  and  rough-turn  with  tool  B,  rough-counterbore  with 
tool  C,  recess  with  tool  D,  drill  with  tool  E,  tap  with  tool  F, 
and  shave  angle  on  body  with  shaving  tool  H  held  on  rear 
of  cross-slide. 

Drilling  Operations  on  Fuse  Body.  — Following  the  ma- 
chining operations  just  described,  the  fuse  body  passes 


Fig.    128.     Stewart   Gas   Furnace   used   for   heating   Castings  pre- 
vious to  hot-pressing 

through  drilling,  counterboring,  and  tapping  operations, 
which  are  performed  on  Leland-Gifford  drilling  machines. 
Fig.  127  gives  the  sequence  of  these  operations. 

The  first  drilling  operation  on  the  machined  body  consists 
in  drilling  the  cap  set-screw  hole  a,  drilling  and  counter- 
boring  the  centrifugal  bolt  hole  b,  and  drilling  the  adapter 
set-screw  hole  c.  For  this  operation,  a  three-spindle  drill- 
ing machine  is  employed.  The  four  operations  are  per- 
formed on  the  three-spindle  machine  because  the  cap  set- 
screw  hole  a  and  the  adapter  set-screw  hole  c  are  the  same 
diameter,  and,  therefore,  machined  by  the  same  drill. 


DETONATING  FUSES 


169 


The  second  set  of  drilling  operations  is  drilling  the  de- 
tent spring  hole  d  with  a  drill  in  one  spindle  of  a  three- 
spindle  drilling  machine.  The  second  spindle  carries  a 


Fig.   129.     Zeh   &   Hahnemann   Percussion   Press   used  in   hot- 
pressing   Fuse  Bodies 

counterboring  tool  that  squares  the  bottom  of  the  hole,  and 
the  third  spindle  carries  a  counterboring  tool. 

The  third  set  of  drilling  operations  is  the  drilling  of  the 


170  DETONATING  FUSES 

hole  for  the  reception  of  the  detent.  This  is  performed  on 
a  two-spindle  drill  press,  each  spindle  carrying  the  same  size 
drill,  except  that  one  is  much  longer  than  the  other.  The 
longer  of  the  two  drills  is  used  with  a  special  fixture  for 


l  • 


Fig.  130.     Close  View  of  Percussion  Press  shown  in  Fig.  129  snow- 
ing Dies  used  and  Casting  before  and  after  forging 


Fig.  131.     Upper  and  Lower  Dies  used  in  Press  shown  in   Fig.  129. 

drilling  two-thirds  of  the  detent  hole  e  from  the  bottom  side. 
The  hole  is  completed  by  drilling  from  the  top,  using  a 
second  fixture  and  the  short  drill  in  the  second  spindle  of 
the  machine. 


DETONATING  FUSES 


171 


The  fourth  set  of  drilling  operations  is  performed  on  a 
three-spindle  drilling  machine.     The  first  spindle  carries  a 


Fig.    132.     Set-up   on   Warner   &   Swasey    Brass- working    Lathe   for 
performing   First  Series  of  Machining  Operations  on   Fuse   Body 


Fig.  133.     Set-up  on  Warner  &  Swasey  Brass-working  Lathe  for 
performing  Second   Series  of  Operations  on    Fuse   Body 

drill  for  drilling  the  central  percussion  pellet  hole  /,  Fig. 
127;  the  second  spindle  carries  a  counterboring  tool;  the 
third  spindle  carries  a  bottoming  tool. 


172 


DETONATING  FUSES 


The  seventh  operation  on  the  fuse  body  is  the  milling  of 
the  oval  wrench  hole  g.  This  is  done  in  a  single-spindle 
drilling  machine,  the  work  being  held  in  a  special  fixture 
so  that  it  may  be  moved  backward  and  forward  slightly 
to  produce  the  oval  hole  required.  The  eighth  operation 


Fig.   134. 


Set-up  on   No.   55  Acme    Multiple-spindle  Automatic 
Screw   Machine  for  machining   Fuse  Cap 


is  the  recessing  of  the  percussion  pellet  hole  h  for  the  thread. 
A  single-spindle  drilling  machine,  equipped  with  a  special 
fixture  to  provide  for  under-cutting,  is  used.  The  ninth  set 
of  operations  consists  in  slightly  countersinking  or  burring 
all  of  the  holes.  This  is  done  with  a  large  countersink  in 
a  single-spindle  drilling  machine,  the  fuse  bodies  being  held 


DETONATING  FUSES  173 

by  hand  against  the  countersink.  The  tenth  and  last  set  of 
operations  consists  in  tapping  five  holes,  namely,  the  set- 
screw  holes  for  the  cap  and  adapter,  the  detent  spring  hole, 
the  centrifugal  bolt  hole  and  the  percussion  pellet  hole. 
Four  separate  machines  are  used  for  tapping,  each  of  which 
carries  a  tapping  head. 

Machining  the  Fuse  Cap.  — The  fuse  cap  C,  Fig.  125,  is 
made  from  brass  rod  1%  inch  in  diameter  in  an  Acme  No.  55 
multiple-spindle  screw  machine,  as  shown  in  Fig.  134.  The 
order  of  operations  is :  Form  and  center,  drill,  bottom,  and 


Fig.  135.     Grant  Riveting  Machines  used  in  riveting  Needle  in 
Percussion  Needle  Plug 

neck,  thread  with  button  die,  and  cut  off.  The  production 
on  this  particular  piece  is  given  in  Table  V;  after  coming 
from  the  screw  machine  it  is  put  through  a  chip  separator 
where  the  oil  and  chips  are  separated.  The  next  operation  is 
drilling  the  two  wrench  holes,  which  is  handled  on  a  single- 
spindle  drilling  machine,  the  jig  being  shifted  on  the  table 
to  drill  the  two  holes. 

Operations  on  Graze  Pellet. — The  graze  pellet  D,  Fig. 
125,  is  made  from  9/16-inch  brass  rod  in  a  No.  52  National- 
Acme  multiple-spindle  automatic  screw  machine.  The  op- 
erations are  as  follows :  Turn  full  diameter  and  also  0.370 
diameter  with  a  double  tool,  also  drill  and  start  neck,  recess 


174 


DETONATING  FUSES  175 

and  continue  neck,  tap  and  finish  neck,  cut  off.  The  piece 
is  finished  on  leaving  the  screw  machine.  The  production 
is  given  in  Table  V,  which  also  includes  a  complete  sum- 
mary of  the  operations  performed  on  the  various  parts  of 
this  fuse. 

There  are  two  drilling  operations  on  the  graze  pellet. 
The  first  consists  in  drilling  the  small  fire  hole  through 
the  entire  length  of  the  piece.  This  is  done  in  a  single- 
spindle  drilling  machine  and  is  followed  by  the  operations 
on  the  upper  end  of  the  piece,  where  the  detonating  cap 
is  held.  The  operations  on  this  end  are  performed  in  a 
three-spindle  drilling  machine ;  the  first  spindle  carries  the 
drill  for  producing  the  large  hole,  the  second  carries  a  coun- 
terboring  tool  and  the  third  a  facing  tool  for  the  bottom  of 
the  hole. 

Operations  on  Centrifugal  Bolt  and  Plugs.  — The  centri- 
fugal bolt  E,  Fig.  125,  is  made  from  brass  rod,  the  opera- 
tions consisting  merely  in  shaving  and  cutting  off.  The 
percussion  detent  plug  G  and  the  percussion  needle  plug  H 
are  also  simple  screw  machine  jobs.  The  needles  are  made 
of  steel  and  are  swaged  down  to  a  fine  point  and  then  hard- 
ened. The  spinning  in  place  of  the  needle  point  is  done  on 
the  Grant  rivet  spinning  machines  shown  in  Fig.  135,  on 
which  a  simple  fixture  shown  by  the  diagram  Fig.  136  is 
employed.  Two  girls  are  employed  on  this  work;  one  in- 
serts the  needles  A  in  plate  B,  and  the  plugs  C  in  plate  D, 
and  the  other  operates  the  machine.  The  holes  in  the  top 
plate  are  large  enough  to  allow  the  needles  to  drop  through 
freely  and  enter  the  plugs;  then  the  top  plate  is  removed 
and  the  fixture  placed  on  the  table  of  the  spinning  machine. 
The  spinning  rolls  are  brought  down  in  contact  with  the 
plugs  consecutively  and  spin  in  the  edge,  holding  the  needles 
firmly  in  place.  The  plugs  are  prevented  from  rotating 
by  steel  inserts  that  are  knurled  on  their  top  faces.  Loca- 
tion of  the  various  holes  under  the  spinning  machine  is  ac- 
complished as  shown  in  the  plan  view,  Fig.  136. 

The  operations  on  the  percussion  detonator  plug  are  per- 
formed on  a  single-spindle  drilling  machine,  and  consist  in 
drilling  the  two  small  holes  with  the  aid  of  a  swivel  jig. 


176 


DETONATING  FUSES 


The  four  small  fire  holes  in  the  percussion  needle  plug  are 
drilled  after  the  needle  has  been  swaged  in  place.  The  drill- 
ing operation  is  left  until  last,  as  otherwise  the  swaging 
operation  would  close  up  the  fire  holes. 

Machining  Operations  on  Percussion  Pellet. —  The  percus- 
sion pellet  /,  Fig.  125,  is  made  from  11/32-inch  diameter 
brass  rods  in  a  multiple-spindle  automatic  screw  machine. 
The  operation  consists  in  turning  with  a  box-tool,  chamfer- 
ing and  squaring  the  threaded  end,  also  drilling  the  hole 
and  squaring  the  bottom,  recessing,  tapping,  and  drilling 
the  small  hole  and  cutting  off.  The  hole  in  the  opposite 


Fig.  137.     Baking  Varnish  on  High-explosive  Shell  Fuses 

end  of  the  percussion  pellet  and  the  one  in  the  side  are 
drilled  in  a  three-spindle  drilling  machine.  The  same  size 
drill  is  used  for  drilling  the  large  cross-hole  and  the  end 
hole.  This  drill  is  held  in  the  first  spindle,  and  a  smaller 
drill,  held  in  the  second  spindle,  drills  the  small  cross-hole, 
whereas  the  third  spindle  carries  a  taper  reamer  for  taper- 
ing the  large  cross-hole. 

Operations  on  Top  and  Bottom  Detents. — The  bottom 
and  top  detents  F  and  L,  respectively,  Fig.  125,  are  made 
with  a  simple  tool  equipment.  The  top  detent  L  is  made 


DETONATING  FUSES 


177 


from  5/32-inch  bronze  rod  in  a  screw  machine,  whereas  the 
bottom  detent  F  is  made  from  brass  rod  7/32-inch  in  diameter 
in  a  screw  machine.  The  operations  on  the  top  detent  are : 
Rough-turn  and  form  head,  finish-turn  and  chamfer,  shave 
from  head  to  point,  and  cut  off.  The  operations  on  the  bot- 
tom detent  are :  Form  and  center,  drill,  form  hole,  and  cut 
off. 

Operations  on  Adapter.  —  The  adapter  shown  at  B,  Fig. 
125,  is  produced  in  three  operations,  the  first  being  per- 


1ST  OPERATION 


FORMING  TOOL        A 


3BD  OPERATION 


DRILL  SMALL  HOLE 


Machinery 


Fig.  138.     Diagram  illustrating  Sequence  of  Operations  on   Galne 

formed  on  an  Acme  No.  55  multiple-spindle  automatic  screw 
machine.  The  first  series  of  operations  is  as  follows: 
Rough-form  and  drill,  shave  and  counterbore,  thread  outside 
diameter,  and  cut  off.  The  second  series  of  operations,  per- 
formed on  a  Cleveland  automatic  screw  machine  provided 
with  a  magazine  attachment  is :  Counterbore,  tap,  and  drill. 
The  third  operation,  performed  in  a  Leland-Gifford  drilling 
machine,  consists  in  drilling  the  two  small  holes.  The  other 
small  parts,  such  as  screws,  etc.,  are  regular  screw  machine 
jobs  and  are  simple  to  manufacture. 


178 


DETONATING  FUSES 


Assembling.  —  The  assembling  is  done  in  the  following 
order:  The  percussion  pellet,  spring,  and  detonator  plug 
are  inserted  in  the  cross-hole;  the  graze  pellet  is  dropped 
into  place ;  the  centrifugal  bolt  and  screw  are  inserted  from 
the  side;  the  combined  detent,  spring,  and  screw  plug  are 
inserted  from  the  base;  the  creeper  spring  is  put  in  from 
the  top  and  the  cap  screwed  in  place.  The  set-screw  for 
the  cap  and  the  adapter  are  then  inserted  and  the  gaine  is 
screwed  in.  The  lacquering  of  the  completed  fuse  is  done 
by  spraying,  and  the  lacquered  fuses  are  baked  in  a  rotat- 
ing oven,  shown  in  Fig.  137,  until  the  varnish  is  dry. 


XS) 


ASSEMBLY  OF  GAINE 


12  T.P.I.  R.H. 


Machinery 


Fig.  139.     Assembly  and  Details  of  Gaine  used  in  British  No.  100 
Graze   High-explosive  Shell   Fuse 

This  oven  has  six  shelves  that  work  on  the  principle  of  a 
Ferris  wheel. 

Machining  British  High-explosive  Fuse  Gaine  Parts.  — 
The  gaine  that  forms  the  exploder  member  of  the  British 
No.  100  graze  fuse  shown  in  Fig.  9  is  shown  assembled  and 
in  detail  in  Fig.  139.  As  shown,  the  gaine  comprises  three 
parts,  viz.,  body  A,  center  plug  B,  and  closing  or  bottom 
plug  C.  The  body  A  of  the  gaine  is  made  from  cold-rolled 
steel,  and  in  one  plant  the  first  operation  is  handled  in  a 


DETONATING  FUSES  179 

No.  53  Acme  multiple-spindle  automatic  in  the  order  shown 
in  Fig.  138.  The  order  of  machining  operations  performed 
at  the  first  chucking  is  shown  from  A  to  C  inclusive,  and 
is  as  follows:  First  position,  drill  large  hole  one-third 
depth,  using  floating  drill-holder,  and  form  the  thread 
diameter  from  cross-slide ;  second,  drill  large  hole  to  shoul- 
der ;  third,  drill  small  hole ;  fourth,  cut  off.  In  the  drilling, 
a  stepped  lead  cam  is  used  so  that  the  drills  can  be  backed 
out  to  clean  out  the  chips  and  assist  the  lubricant  in  getting 
to  the  cutting  points  of  the  drills.  The  outer  surface  of  the 
gaine  is  not  finished  and  the  holes  are  not  reamed.  The 
cutting  speed  is  100  surface  feet  per  minute,  and  the  produc- 
tion is  sixty  per  hour. 

The  second  series  of  operations,  shown  in  Fig.  138,  is  per- 
formed on  a  No.  2  plain-head  Warner  &  Swasey  turret  lathe, 
as  follows:  First,  ream  the  four  diameters  of  the  hole 
with  a  stepped  reamer;  second,  under-cut  at  the  bottom  of 
the  two  threaded  sections,  this  is  done  with  a  tool  having 
two  cutting  points  properly  spaced ;  third,  tap  the  two  holes 
with  a  double-threaded  tap.  The  production  is  thirty  pieces 
per  hour  and  the  cutting  speed,  except  for  the  tapping,  is 
100  surface  feet  per  minute. 

The  third  series  of  operations,  shown  to  the  right  in  Fig. 

138,  is  performed  on  a  No.  2  plain-head  Warner  &  Swasey 
turret  lathe,  and  the  piece  is  held  with  the  threaded  end 
outward.     The  operations  are:    First,  center;  second,  drill 
large  hole;  third,  form  bottom  of  hole;  fourth,  drill  small 
hole  with  a  high-speed  drilling  attachment;  fifth,  thread 
external  diameter  with  a  self-opening  die.     The  cutting 
speeds  on  this  operation  are  100  surface  feet  per  minute 
and  the  production  is  thirty  pieces  per  hour.     In  the  plant 
where  this  information  was  obtained,  considerable  trouble 
was  experienced  in  drilling  the  small  hole.     Attempts  were 
made  to  produce  this  hole  in  a  high-speed  drilling  ma- 
chine, with  poor  results.    The  method  shown  at  /  is  recom- 
mended as  being  more  satisfactory,  as  in  this  case  both 
work  and  drill  revolve. 

Machining  the  Center  Plug. — The  center  plug  B,   Fig. 

139,  is  made  from  hot-rolled  machine  steel  and  is  completed 


180  DETONATING  FUSES 

in  two  operations.  The  first  series  of  operations  is  per- 
formed on  a  No.  53  Acme  multiple-spindle  automatic.  The 
operations  are :  Form  the  entire  length  of  the  piece  and  drill 
small  hole,  shave  outside  diameter  and  square  bottom  of 
hole,  thread,  and  cut  off.  The  second  series  of  operations 
is  performed  on  a  No.  2  plain-head  Warner  &  Swasey  turret 
lathe  in  the  following  order:  Center  drill,  drill,  form  hole 
with  special  counterboring  tool,  and  face  end  with  tool  on 
rear  cross-slide.  These  pieces  are  handled  at  the  rate  of 
forty-five  per  hour.  The  work  on  this  piece  is  completed  by 
a  simple  slotting  operation  on  an  Acme  screw  slotter.  The 
machining  of  the  bottom  plug  C  is  performed  on  a  No.  53 
Acme  multiple-spindle  automatic.  This  part  is  made  of 
cold-rolled  steel  and  turned  at  a  speed  of  100  surface  feet 
per  minute.  The  order  of  operations  is:  Form  external 
diameter,  face  end,  thread,  and  cut  off.  This  piece  is  pro- 
duced at  the  rate  of  180  per  hour.  The  drilling  of  the  two 
holes  in  the  end  of  this  plug  is  performed  in  a  drilling  ma- 
chine with  the  aid  of  a  simple  jig. 


CHAPTER  X 
HIGH-EXPLOSIVE  CARTRIDGE  CASE  MANUFACTURE 

THE  cartridge  case  used  in  the  British,  18-pound,  quick- 
firing,  field  gun  is  made  from  an  alloy  of  copper  and  zinc, 
generally  70  per  cent  electrolytic  copper  and  30  per  cent 
zinc.  The  exact  composition  of  the  alloy  is  left  to  the  dis- 
cretion of  the  manufacturer,  but  the  completed  cartridge 
case  must  have  the  required  strength  and  elasticity.  The 
number  of  redrawing  and  annealing  operations  on  the  case 
is  never  less  than  six,  while  two  tapering  operations  must 
also  be  performed  to  bring  the  mouth  of  the  shell  to  the  cor- 
rect diameter  and  the  body  to  the  right  shape.  The  prac- 
tice followed  in  plants  making  this  case  does  not  differ  ma- 
terially in  regard  to  the  number  of  drawing  operations,  but 
there  is  some  difference  in  the  methods  used  in  handling 
the  work.  The  following  description  covers  the  method 
used  by  a  large  concern  that  turns  out  4000  18-pound  cart- 
ridge cases  per  day  of  ten  hours. 

Blanking  and  Cupping.  —  The  first  operation  on  the  cart- 
ridge case  is  to  cut  out  a  blank  6.22  inches  in  diameter  from 
a  sheet  0.380  inch  thick.  This  operation  is  seldom  handled 
by  the  firm  making  the  cartridge  cases,  most  firms  prefer- 
ring to  buy  the  blanks  from  manufacturers  that  make  a  spe- 
cialty of  this  business.  The  blank  is  usually  cut  out  in  a 
geared  punch  press  at  the  rate  of  about  400  blanks  per  hour. 
Usually  the  blank  is  in  the  annealed  condition  when  received 
by  the  cartridge  case  manufacturer.  Assuming  that  the 
blank  is  purchased  in  the  annealed  condition,  the  first  opera- 
tion is  cupping.  In  the  plant  where  the  following  data 
was  obtained,  this  operation  is  performed  in  a  Toledo  press, 
as  shown  in  Fig.  140.  One  operator  can  turn  out  4000  cups 
in  ten  hours.  On  this  operation,  a  production  as  high  as 
600  per  hour  can  be  obtained,  but  this  pace  cannot  be  kept 

181 


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183 


184 


CARTRIDGE  CASE  MANUFACTURE 


up  by  one  man.  The  shape  and  size  of  the  cup  after  the 
cupping  operation  is  shown  at  B,  Fig.  143.  Table  VI  gives 
the  complete  order  of  operations. 

Annealing.  —  Following  the  cupping  operation,  the  metal 
is  hardened  somewhat  and,  consequently,  annealing  is  neces- 
sary to  restore  the  required  ductility.  The  hardness  of  the 
metal  is  also  tested  by  means  of  the  scleroscope  after  each 
press  and  annealing  operation,  and  in  this  plant  one  per 
cent  of  the  daily  production  is  given  this  test.  The  anneal- 


Fig.    140.     First   Operation— Cupping   in   a  Toledo   Press 

ing  is  done  in  a  special  furnace,  shown  in  Fig.  141,  which 
is  about  6  feet  wide  by  24  feet  long.  The  cases  are  loaded 
into  trays  and  fed  into  the  furnace  at  the  loading  end  by 
a  ram  operated  by  compressed  air.  These  trays  hold,  on 
an  average,  fifty-six  cups,  the  number  depending  on  the 
diameter  of  the  case,  and  each  furnace  holds  eight  trays. 
The  furnaces  are  kept  at  a  constant  temperature  of  1250 
degrees  F.  (about  680  degrees  C.),  and  the  cups  are  an- 
nealed for  one  hour  and  four  minutes  at  this  temperature. 
This  is  the  average  length  of  time  that  each  tray  is  allowed 


CARTRIDGE  CASE   MANUFACTURE 


185 


to  remain  in  the  furnace,  but  the  loading  and  unloading  is 
carried  on  every  eight  minutes.  As  soon  as  the  cups  are 
removed  from  the  furnace  they  are  immersed  in  water. 
There  are  six  pyrometers  in  each  furnace  for  controlling  the 
temperature,  three  on  each  side ;  these  pyrometers  are  tested 
every  fifteen  minutes,  as  shown  in  Fig.  142,  so  that  any 
variation  in  the  temperature  of  the  furnaces  can  be  imme- 
diately checked  up.  After  cooling  in  water,  the  cups  are 
placed  in  a  pickling  bath,  which  consists  of  twenty  parts 
water  to  one  part  sulphuric  acid.  When  removed  from  this, 


Fig.  141.     Annealing  Cartridge  Cases 

they  are  immersed  in  a  high  caustic  soda  bath,  and  are  then 
washed  in  warm  water  to  remove  all  traces  of  the  acid. 

All  firms  engaged  in  this  work,  however,  do  not  follow 
this  procedure  in  cooling  and  washing.  One  concern  be- 
lieves that  the  rapid  cooling  of  the  cases  in  water  affects 
their  physical  properties,  and,  hence,  allows  the  cases  to  cool 
off  in  the  air  after  each  annealing  operation.  When  cool, 
the  cases  are  immersed  in  a  bath  containing  a  weak  solution 
of  sulphuric  acid  and  then  in  a  weak  bath  of  cyanide  of 
potassium,  after  which  they  are  rinsed  in  water. 


186 


CARTRIDGE  CASE  MANUFACTURE 


First  and  Second  Redrawing  and  Indenting  Operations. — 
Following  the  cleaning  of  the  cups,  they  are  taken  to  an- 
other Toledo  press,  shown  in  Fig.  145,  where  the  first  re- 
drawing operation  is  accomplished.  For  this,  one  machine 
and  two  men  are  required  for  a  production  of  400  per  hour. 
It  will  be  noticed  in  Fig.  143,  at  C,  that  the  thickness  of  the 
bottom  of  the  case  remains  the  same,  the  sides  alone  being 
reduced  in  thickness  and  increased  in  length ;  it  is  important 
that  this  thickness  at  the  base  is  retained.  After  this,  the 


Fig.  142. 


Recording   Instruments  used  in  checking  up  Temperature 
of  Annealing  Furnaces 


cases  are  annealed,  washed,  etc.,  as  before.  The  only  dif- 
ference here  is  that  the  pan  holds  sixty-three  instead  of 
fifty-six  cases,  due  to  the  smaller  diameter  of  the  cases. 

The  second  redrawing  operation  D,  Fig.  143,  is  accom- 
plished in  the  same  manner  as  the  first,  and  the  produc- 
tion is  also  the  same,  400  per  hour,  two  operators  being 
required.  Following  the  second  redrawing  operation,  the 
cups  are  taken  directly  to  the  first  indenting  operation,  the 
result  of  which  is  shown  at  E,  Fig.  143.  This  operation  is 
accomplished  in  the  Toledo  press  shown  in  Fig.  146.  It  will 


CARTRIDGE  CASE  MANUFACTURE 


187 


be  noticed  that  for  indenting  the  case  is  placed  on  the  lower 
punch  A.  Upon  the  descent  of  punch  B,  the  lower  punch 
is  forced  down  into  the  die,  exposing  the  indenting  punch 
that  is  located  inside  of  it.  The  case  also  goes  down  into 
the  die  and  consequently  is  prevented  from  being  distorted. 
Upon  the  up-stroke,  the  case  is  ejected  from  the  die  by  the 


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Fig.  143.     Sequence  of  Operations  on   British  18-pound 
High-explosive  Shell  Cartridge  Case 

double  action  of  the  press,  and  to  provide  against  any 
chances  of  its  sticking  on  the  punch  B,  an  ejector  C  is  pro- 
vided. In  this  operation,  only  one  operator  is  required  and 
the  production  is  300  per  hour.  The  important  point  to 
observe  in  this  case  is  the  depth  of  the  indent  E,  Fig.  143, 
which  must  be  7/16  inch.  Following  indenting,  the  cases 
are  again  annealed,  each  pan  holding  sixty-eight  cases. 


188 


CARTRIDGE  CASE  MANUFACTURE 


1 


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M   COMPLETED  CARTRIDGE  CASE     '  Machinery 


Fig.  144.     Sequence  of  Operations  on  British  18-pound  High-explosive 

Shell  Cartridge  Case — Continued  (Thickness  of  Walls  Slightly 

Exaggerated) 

Third  and  Fourth  Redrawing  and  Second  Indenting  Oper- 
ations.—  The  third  redrawing  operation  is  accomplished 
in  a  No.  57  Toledo  press,  as  shown  in  Fig.  147.  The  pro- 


CARTRIDGE  CASE  MANUFACTURE 


189 


duction  on  this  operation  is  200  cases  per  hour  and  the  case 
is  drawn  out  to  the  length  shown  at  F,  Fig.  143,  and  also 
reduced  slightly  in  diameter.  Two  operators  are  required 
for  this  operation.  After  redrawing,  the  case  is  annealed, 
washed,  etc.,  as  before.  The  annealing  pans  accommodate 
seventy-two  cases  each. 


Fig.   145. 


First  Redrawing  Operation  performed  on  a  Toledo  No.  59 
Press 


The  fourth  redrawing  operation  is  accomplished  in  a  No. 
857  Toledo  press ;  the  production  is  150  cases  per  hour,  and 
two  operators  are  required.  The  result  of  this  operation  is 
shown  at  G,  Fig.  143.  Following  the  fourth  redrawing  op- 
eration, the  cartridge  case  is  given  the  second  indent,  as 
shown  in  Fig.  148.  Reference  to  H,  Fig.  144,  will  show  that 
the  head  of  the  case  is  somewhat  flattened  in  this  operation, 


190 


CARTRIDGE  CASE  MANUFACTURE 


leaving  a  projection  raised  around  the  outer  rim.  The 
depth  from  the  flat  surface  of  the  head  to  the  bottom  of  the 
indent  is  the  most  important  dimension;  this  depth  on  the 
18-pound  cartridge  case  must  be  17/32  inch.  The  produc- 
tion at  this  operation,  two  operators  being  employed,  is  250 
cases  per  hour.  Following  the  second  indent,  the  cases  are 
again  annealed,  washed,  etc.  The  pans,  in  this  case,  carry 


Fig.   146.     First   Indent  on   a  Toledo   Press 

seventy-eight  cases  because  of  the  reduced  diameter.  The 
presses  used  in  performing  the  cupping,  redrawing,  reduc- 
ing, and  heading  operations  vary  in  ram  capacity  from  500 
to  1200  tons  pressure  per  square  inch. 

Fifth  and  Sixth  Redrawing  and  Second  Trimming  Oper- 
ations. —  Following  the  second  indent,  the  fifth  redrawing 
operation  is  accomplished  in  a  No.  857  Toledo  press;  the 
production  being  150  per  hour.  The  condition  of  the  case 


CARTRIDGE  CASE  MANUFACTURE 


191 


after  this  operation  is  shown  at  I,  Fig.  144.  Before  anneal- 
ing, the  mouth  end  of  the  case  is  trimmed  because  the  case 
becomes  quite  ragged  on  the  mouth  end  and  would  tear  in 
the  sixth  redrawing  operation  if  the  excess  stock  were  not 
removed.  The  total  length  of  the  case  after  the  fifth  re- 
drawing operation  averages  10%  inches  and  it  is  trimmed 
to  lOi/2  inches.  In 
many  cases,  as  the 
punch  wears  small,  it 
is  not  necessary  to  per- 
form this  trimming 
operation  because  the 
wall  is  thicker.  The 
shape  of  the  simple 
disk  cutter  is  shown  in 
Fig.  149,  and  the 
method  of  trimming 
the  mouth  of  the  case 
in  the  Toledo  trim- 
ming machine  is 
shown  in  Fig.  150. 

Two  operators  are 
necessary  for  this 
trimming  operation ; 
one  holds  the  case  on 
the  arbor  and  the 
other  does  the  trim- 
ming; the  production 
is  350  per  hour.  Some 
changes  have  been 
made  in  this  machine. 
The  regular  cutter 
head  has  been  removed  and  a  cross-slide  substituted.  This 
cross-slide  is  operated  by  a  lever,  as  shown,  and  carries  a 
toolpost  to  which  a  circular  friction  disk  cutter  A  is  held. 
After  trimming,  the  cases  are  annealed,  each  pan  holding 
eighty-eight  cases. 

The  sixth  redrawing  operation  is  performed  on  a  Toledo 


Fig.  147.     Third   Redrawing  Operation  on  a 
Toledo  No.  57  Press 


192 


CARTRIDGE  CASE   MANUFACTURE 


No.  856  press.  The  case,  at  this  operation,  is  quite  long 
so  that  the  production  is  reduced  to  120  per  hour,  with  two 
operators.  In  this  operation,  the  important  dimension  is 
the  thickness  of  the  wall  at  the  mouth ;  this  should  be  0.0285 
inch.  Following  this  redrawing  operation,  the  case  is 
again  trimmed,  as  shown  in  Figs.  149  and  150.  The  pro- 


Fig.  148.     Second  Indenting  Operation  on  a  Toledo  Press 

duction  on  the  trimming  machine  is  350  cases  per  hour. 

Heading.  —  After  the  sixth  redrawing  and  trimming  op- 
erations, the  cartridge  case  is  taken  directly  to  the  Toledo 
heading  press,  shown  in  Fig.  151.  The  operation  of  this 
press  is  as  follows:  An  indexing  fixture  fastened  to  the 
ram  of  the  press  carries  two  heading  punches,  one  being 
used  for  forming  the  primer  pocket  and  the  other  for  flat- 


CARTRIDGE  CASE  MANUFACTURE 


193 


Fig.  149.     Close  View  of  Cartridge  Case  Trimming  Machine  shown 
in    Fig.    150 


Fig.  150.     Trimming   Mouth   End  of  Case  on  a  Toledo  Cartridge 
Case   Trimming    Machine 


194 


CARTRIDGE  CASE  MANUFACTURE 


tening  out  the  head.  The  heading  die-holder  retained  on 
the  bed  of  the  press  is  also  of  the  indexing  type.  The  die- 
holder  C  carries  two  similar  shaped  heading  dies  A  and  Z>, 
each  of  which  carries  a  bottom  plug,  or  support,  for  the 
cartridge  case.  Assuming  that  both  dies  A  and  D  are 
empty,  the  cartridge  case  is  placed  over  the  plug  in  the  die, 

then  the  turret  die- 
holder  C  is  indexed, 
bringing  the  loaded 
die  in  line  with  the 
punches.  Next,  punch 
B  is  indexed  in  line 
with  the  cartridge 
case;  after  this,  the 
press  is  operated  and 
the  first  blow  deliv- 
ered. The  die-holder 
now  remains  station- 
ary and  the  punch- 
holder  is  indexed  to 
bring  the  flattening 
punch  in  line,  after 
which  the  press  is 
again  operated  and 
the  second  blow  deliv- 
ered. An  unheaded 
case  is  now  loaded  in 
the  empty  die,  and  the 
die  turret  indexed ; 
this  brings  the  un- 
headed case  in  line  with  the  ram,  and  the  headed  case  in 
line  with  the  pick-up  E.  The  punch-holder  is  now  indexed 
to  again  bring  the  punch  B  in  line,  and  the  press  operated. 
While  the  blow  is  being  delivered  to  the  second  case,  the 
headed  case  is  removed  from  the  die  turret  by  pick-up  E. 
The  production  is  150  cases  per  hour. 

Following  heading,  the  mouth  of  the  shell  is  annealed  pre- 
vious to  the  tapering  operations  that  follow.     The  anneal- 


Fig.    151. 


Heading   Cartridge   Cases  on   a 
Toledo  Press 


CARTRIDGE  CASE  MANUFACTURE  195 

ing  is  accomplished  as  shown  in  Fig.  152.  The  machine 
comprises  a  rotating  table  carrying  twelve  plates,  which  are 
also  rotated,  upon  which  the  cartridge  cases  are  placed. 
Twenty  burners  fed  by  natural  gas  are  provided.  The 
large  table  makes  one  revolution  in  one  minute  and  forty 
seconds,  but  the  cartridge  cases  are  rotated  continuously 
and  make  thirty-three  revolutions  to  each  revolution  of  the 
large  table.  The  main  rotating  fixture  carries  a  large  spur 
gear  that  meshes  with  small  pinions  fastened  to  the  spindles 
of  the  plates  that  carry  the  cases ;  hence,  as  the  large  fixture 
rotates,  the  plates  carrying  the  cases  are  also  rotated.  One 


Fig.  152.     Annealing   Mouth  In  a  Special  Furnace  previous  to 
tapering 

revolution  of  the  large  table  anneals  the  mouth  of  the  case 
sufficiently  for  tapering.  The  annealing  temperature  at- 
tained at  this  time  is  about  800  degrees  F.  (about  430  de- 
grees C.),  which  is  sufficient  to  heat  the  cartridge  cases  to 
a  cherry-red  color.  Prior  to  the  tapering  operations  which 
follow,  the  cases  are  washed  in  a  10  per  cent  caustic  soda 
and  water  solution. 

Tapering.  —  Following  the  annealing  of  the  mouth  of  the 
case,  two  tapering  operations  are  performed,  bringing  the 
case  to  the  final  shape  shown  at  M,  Fig.  144.  These  opera- 
tions are  performed  in  Toledo  special  tapering  presses,  which 
are  shown  in  Fig.  153.  These  machines  differ  from  the  or- 


196 


CARTRIDGE  CASE  MANUFACTURE 


dinary  punch  press  in  that  the  stroke  of  the  press  is  con- 
trolled by  an  eccentric  and  link  motion  instead  of  by  a  com- 
bined crank  and  toggle  action.  This  mechanism  is  used 
owing  to  the  length  of  stroke  necessary  and  because  of  the 
fact  that  a  press  used  for  tapering  does  not  need  anywhere 


Fig.    153.     First   and    Second   Tapering    Operations   on    Special 
"Toledo"   Cartridge   Case  Tapering    Machines 

nearly  the  same  strength  and  power  as  one  that  would  be 
used  for  heavy  redrawing,  embossing,  or  forming  opera- 
tions. 

In  the  first  tapering  operations,  the  mouth  of  the  case  is 
reduced  to  3%  inches  in  diameter  and  tapered  for  a  distance 


CARTRIDGE  CASE  MANUFACTURE 


197 


of  6  inches,  the  diameter  at  the  termination  of  the  taper 
being  3%  inches.  Two  men  are  employed  for  this  opera- 
tion and  the  production  is  250  per  hour.  In  the  second  tap- 
ering, the  mouth  of  the  shell  is  made  straight  for  one  inch 
and  then  tapered  to  the  rim  on  the  head  at  the  rate  of 
0.04066  inch  on  the  diameter  for  every  inch  in  length.  Two 
men  can  produce  250  cases  per  hour  on  this  operation. 


Fig.   154.     Machining   Head  and   Mouth   Ends  of  Case  on  a   Bullard 
Cartridge  Case  Trimming,   Facing  and  Chamfering   Machine 

Machining  Cartridge  Cases.  —  The  cartridge  case  is  not 
finished  complete  in  the  punch  press,  but  after  tapering, 
several  operations  are  performed  on  the  head  and  mouth, 
and  these  are  handled  on  the  Bullard  cartridge  case  trim- 
ming, chamfering  and  facing  machine  shown  in  Fig.  154. 
The  operations  are :  Rough-bore  primer  pocket,  face  head 


198 


CARTRIDGE  CASE  MANUFACTURE 


with  facing  tool,  form  with  tool  on  rear  of  carriage,  recess 
at  bottom  of  primer  pocket,  tap  with  Murchey  tap,  four 
threads  per  inch,  ream  with  a  combination  reamer,  and  turn 
and  trim  open  end. 

Inspecting  and  Testing. —  The    cartridge    case    is    now 
turned  over  to  the  inspectors,  when  the  following  gaging 


? 

1 

1     I 

j        ! 

( 

Machinery 


Fig.  155.     Diagram  showing  Application  of  Various  Gages  used  in 
inspecting  18-pound   British  Cartridge  Cases 

tests  are  made:  First,  gage  for  thickness  of  head;  second, 
for  tapers ;  third,  over-all  length ;  fourth,  thickness  through 
primer  hole;  fifth,  primer  hole  diameter;  sixth,  root  of 
thread ;  seventh,  lower  rim ;  eighth,  thickness  of  head ;  ninth, 
thickness  of  head  flange ;  tenth,  diameter  of  counterbore  at 
extreme  head  of  case;  eleventh,  recess  in  pocket;  twelfth, 
threads ;  and  thirteenth,  gun  barrel  test. 


CARTRIDGE  CASE  MANUFACTURE  199 


Fig.  156.     Gaging  Thickness  of  Head  of  Cartridge  Case 


Fig.  157.     Testing  Taper  of  Cartridge  Case  with  Horseshoe  Gages 


200  CARTRIDGE  CASE  MANUFACTURE 

The  manner  in  which  these  inspection  operations  are 
handled  is  shown  diagrammatically  in  Figs.  155  and  162  and 
in  Figs.  156  to  161,  inclusive.  The  first  test  that  is  made 
is  for  the  thickness  of  the  head,  measuring  from  the  inside. 
This  is  accomplished  as  shown  in  Fig.  156,  and  diagramma- 
tically at  A,  Fig.  155.  The  cartridge  case  is  held  on  a  post 
a,  and  the  swinging  arm  b  that  rests  on  the  shoulder  of  an- 
other post  c  carries  two  gaging  points  d  and  e,  one  being 
set  for  the  maximum  and  the  other  for  the  minimum  dimen- 
sions. A  limit  of  0.002  inch  is  allowed. 


Fig.  158.     Gaging  Over-all   Length  of  Case 

Gaging  for  taper  is  accomplished  by  means  of  horseshoe 
gages,  as  shown  in  Fig.  157,  and  diagrammatically  at  B,  Fig. 
155.  The  upper  gage  i  measures  at  a  point  8.25  plus  0.000, 
minus  0.005  inch  from  the  head  and  the  lower  gage  j  at  a 
point  3.428  plus  0.000,  minus  0.002  inch  from  the  head. 
The  limit,  as  shown  at  B,  is  0.002  inch  for  the  smaller  diame- 
ter, whereas  the  larger  diameter  has  a  limit  of  0.005  inch. 
The  third  test  is  for  over-all  length,  as  shown  in  Fig.  158, 
and  at  C,  Fig.  155.  Here  the  case  is  held  on  a  baseplate 


CARTRIDGE  CASE  MANUFACTURE 


201 


/  and  the  gaging  bar  g  is  held  on  a  standard  h,  a  limit  of 
0.040  inch  being  allowed  on  the  length. 

The    test    shown    in    Fig.    159    and    at    D,    Fig.    155, 


Fig.    159. 


Gaging  Thickness  of  Flange  and  Thickness  through 
Primer  Hole 


Fig.  160.     Gaging  Diameter  of  Head  and  Depth  of  Counterbore 

is  gaging  the  thickness  from  the  head  of  the  case  to  the 
inner  face  of  the  pocket.  The  allowable  limit  here  is  0.010 
inch.  First,  the  clearance  hole  in  the  primer  pocket  is  gaged 


202 


CARTRIDGE  CASE  MANUFACTURE 


as  shown  atE,  Fig.  155;  afterwards,  the  root  diameter  of  the 
threaded  hole  is  tested,  as  shown  at  F.  Following  this,  the 
diameter  of  the  head  of  the  case  is  tested,  as  shown  to  the 
right  in  Fig.  160,  and  at  G,  Fig.  155.  Here  the  head  is 
gaged  at  three  points,  the  limits  being  as  shown  at  G. 


Fig.    161.     Making    Gun    Barrel    Test 

The  final  gaging  operations  are  shown  at  H,  I,  and  J, 
Fig.  155,  and  in  Figs.  161  and  162.  The  thickness  of  the 
head  is  gaged  as  shown  at  H  and  /,  and  also  to  the  right 
in  Fig.  159.  The  gage  used  is  of  the  double-ended  type,  so 
that  the  two  thicknesses  can  be  measured  with  one  gage. 
The  next  test  is  to  gage  the  diameter  of  the  counterbore  in 
the  head  of  the  cartridge  case  as  shown  at  /.  Following 
this,  the  last  and  final  test  is  made ;  this  is  the  gun  barrel 


CARTRIDGE  CASE  MANUFACTURE 


203 


test  shown  in  Figs.  161  and  162.  This  gage  comprises  a  cylin- 
drical cast-iron  tube,  which  is  machined  inside  to  the  same 
dimensions  as  the  bore  of  the  barrel,  as  shown  in  Fig.  162,  and 

TABLE  VII.     SCLEROSCOPE  READINGS  INDICATING  HARD- 
NESS OF  METAL  AFTER  EACH  ANNEALING  AND 
REDRAWING  OPERATION 


C 

A 

J 

7 

on 

i 

r 
i 

I 

i  •. 

BL 

1  ) 

-^/ 

MMK 

3/ 

\^777?\ 
p-i£?| 

i—  - 

r" 

3- 

^         J 

?\ 

^      \\ 

1ST  INDENT 

1 

y 

COMPLETED  CASE 

Operation 

Time 

Points  i 

it  which  Readings  are  Taken 

of 

OI 

Test 

7 

1 

2 

3 

4    1 

5 

6 

8 

9 

10 

11 

Blanking 

A* 

15 

14 

14 

14 

15 

14 

Cupping 

B 

20 

26 

31 

19 

50 

46 

Annealed 

A 

12 

12 

12 

11 

13 

12 

First  Redrawing 

B 

11 

13 

19 

14 

36 

50 

Annealed 

A 

12 

12 

12 

11 

12 

11 

Second  Redrawing 

B 

12 

10 

12 

36 

50 

50 

First  Indenting 

B 

34 

35 

22 

44 

44 

46 

Annealed 

A 

11 

11 

11 

15 

14 

14 

Third  Redrawing 

B 

11 

12 

12 

\ 

\ 

\  \ 

36 

41 

48 

\\ 

'  \ 

Annealed 

A 

10 

11 

12 

12 

14 

15 

Fourth  Redrawing 

B 

11 

11 

12 

\ 

31 

38 

44 

Second    Indenting 

B 

12 

26 

34 

t 

. 

34 

51 

51 

Annealed 

A 

10 

11 

12 

12 

14 

14 

Fifth  Redrawing 

B 

14 

12 

15 

( 

32 

35 

41 

41 

Annealed 

A 

11 

13 

14 

t 

t 

§ 

15 

11 

14 

15 

Sixth  Redrawing 

B 

13 

20 

15 

. 

, 

,  , 

22 

30 

31 

41 

42 

Heading 

16 

38 

47 

. 

. 

, 

28 

32 

33 

44 

45 

Mouth  Anneal 

16 

38 

46 

26 

30 

31 

22 

12 

Second  Taper 

16 

37 

46 

, 

35 

38 

44 

36 

59 

Machinery 

•  Note:     "A"   is  scleroscope  reading  before,   and    "B"   after  annealing. 

two  supporting  stands.  The  cartridge  case  is  pushed  into  this 
gage,  and  by  laying  a  scale  across  the  gage,  the  head  of  the 
cartridge  case  must  come  slightly  below  flush.  The  case  should 
be  easily  inserted  and  extracted  from  this  gage. 


204 


CARTRIDGE  CASE  MANUFACTURE 


Testing  Cartridge  Cases  for  Hardness.  —  In  order  that 
the  final  product  will  be  according  to  specifications,  each 
drawing  and  annealing  operation  must  be  carefully  fol- 
lowed. The  method  generally  adopted  by  various  manufac- 
turers engaged  in  this  work  is  to  use  the  scleroscope  and 
test  the  hardness  of  the  case  before  and  after  each  redraw- 
ing or  annealing  operation.  Table  VII  gives  the  readings 
taken  on  the  cartridge  case  after  each  operation,  and  the 
diagram  with  this  table  shows  the  points  at  which  the  read- 
ings are  taken.  It  is  the  practice  of  this  plant  to  "sclero- 
scope" 1  per  cent  of  its  daily  product ;  therefore,  on  a  prod- 
uct of  4000  cartridge  cases  in  ten  hours,  forty  cases,  after 


Machinery 


Fig.  162.     Diagram  showing  Gage  used  for  Gun   Barrel  Test 

the  completion  of  each  operation,  as  shown  in  Fig.  163,  are 
taken  to  the  testing  department  where  scleroscope  readings 
are  taken.  These  readings  are  then  charted  and  compared 
with  other  tests. 

Making  Primers  for  Cartridge  Cases. —  The  percussion 
primer,  carried  in  the  head  end  of  the  cartridge  case  and 
used  for  igniting  the  propelling  charge,  comprises  six  parts, 
as  shown  in  Fig.  164.  Of  these,  the  body  A  is  the  most  dif- 
ficult to  make.  This  is  made  from  1  7/16-inch  round  bar 
stock,  either  in  a  hand  or  automatic  screw  machine.  In 
one  plant  turning  these  parts  out  in  large  quantities,  a  Grid- 
ley  1%-inch  multiple-spindle  automatic  screw  machine,  as 


CARTRIDGE  CASE  MANUFACTURE 


205 


shown  in  Fig.  165,  is  used  for  performing  the  first  series 
of  operations.  The  order  of  operations  is  as  follows :  Rough- 
counterbore  and  form,  drill  and  countersink,  thread  exter- 
nal diameter,  and  finish-ream,  cut  off,  and  feed  stock.  The 
spindles  of  the  machine  are  rotated  so  as  to  give  a  speed 
of  90  surface  feet  for  the  forming  cut.  The  production  is 
eighty  per  hour. 

The  second  operation  on  the  body  consists  in  facing  and 
shaving  the  head ;  this  is  done  on  a  hand  screw  machine  of 
the  Pratt  &  Whitney  type.  The  work  is  rotated  to  give  a 


Fig.  163.     Testing  Hardness  of  Cartridge  Case  with  Scleroscope 

surface  speed  of  125  feet  per  minute,  and  the  production 
is  250  per  hour.  The  third  operation  is  milling  the  key 
slots  in  the  base  in  a  Brown  &  Sharpe  hand  milling  machine, 
using  a  simple  indexing  fixture.  The  end-mill  used  is  op- 
erated at  200  feet  surface  speed,  and  one  cut  finishes  each 
slot.  The  production  is  140  per  hour.  The  fourth  opera- 
tion, reaming  the  tap  hole  and  the  smaller  hole  in  the  base 
of  the  body,  is  done  in  a  Henry  &  Wright  two-spindle  drill- 
ing machine  carrying  a  combination  reamer.  The  work 
is  held  in  a  fixture  that  can  be  slid  along  the  table,  being 
controlled  in  its  movement  by  guide  strips  fastened  to  the 


206 


CARTRIDGE  CASE  MANUFACTURE 


-PAPER  DISK  SECURED  WITH  PETTMAN  CEMENT 
OUTSIDE  TO  BE  COATED  WITH  A  THIN  LAYER 


—  PAPER  DISK  SECURED  WITH  PETTMAN  CEMENT 
COATED  WITH  PETTMAN  CEMENT  UNDER  TURNOVER 


SLOTS  TO  BE  CUT  BY  SHEARING  OR 
IF  SAWED,   NOT  TO  EXCEED  0.011 


CLOSING  DISK-BRASS 


Machinery 


Fig.  164.     Assembly  View  and  Details  of  British  Cartridge  Case  Primer 


CARTRIDGE  CASE  MANUFACTURE  207 

table.  Two  tools  are  used,  one  for  roughing  and  the  other 
for  finishing,  the  surface  speed  being  about  200  feet.  The 
production  on  this  operation  is  about  150  per  hour. 

The  fifth  operation  is  to  tap  the  small  hole  in  a  tapping 
machine  with  a  tap  operating  at  a  surface  speed  of  30  feet 
per  minute.  The  work  is  held  in  a  jig  and  the  production 
is  120  per  hour.  The  sixth  operation  is  to  finish-ream  the 
percussion  cap  hole  in  a  Henry  &  Wright  drilling  machine. 
This  is  a  very  difficult  operation  to  accomplish  because  the 


Fig.   165.     Machining  Cartridge  Case  Primer  Body  on  a  Gridley 
1%-inch  Automatic 

accuracy  required  is  ±  0.0005  inch.  The  surface  speed  of 
the  tool  has  to  be  cut  down  to  80  feet;  and  the  production 
is  100  per  hour.  The  seventh  operation  is  to  stamp  the 
required  letters  on  the  base  of  the  primer  with  a  hand 
stamp,  three  sets  of  stamps  being  required.  The  produc- 
tion is  150  per  hour.  The  eighth  is  to  lacquer  the  exterior 
with  a  brush.  The  lacquer  used  consists  of:  Seedlac,  10.54 
per  cent;  turmeric,  5.26  per  cent;  spirits,  methylated,  84.2 
per  cent.  This  is  done  at  the  rate  of  200  per  hour.  The 
ninth  operation  is  inspecting. 


208 


CARTRIDGE  CASE  MANUFACTURE 


Making  the  Disk.  — The  closing  disk  B,  Fig.  164,  for  the 
primer  is  made  from  1-inch  diameter  brass  rod  in  a  11,4-inch 
Gridley  multiple-spindle  automatic  screw  machine.  The  or- 
der of  operations  is  as  follows :  Form  and  cup,  shave,  finish 
cup,  and  cut  off  and  feed  stock.  The  stock  is  operated  at  a 
surface  speed  of  110  feet,  and  the  production  is  at  the  rate 


Fig.  166. 


Slotting  Anvils  in  a  National-Acme  Screw  Slotting 
Machine 


of  20  seconds  a  piece.  The  second  operation  is  to  remove 
the  burrs  on  a  small  stand  grinder.  The  third  operation 
is  to  slit  and  straighten  in  a  small  Brown-Boggs  punch 
press.  The  fourth  is  to  inspect. 

Making  the  Anvil.  —  The  anvil  C,  Fig.  164,  is  made  on  a 
No.  00  Brown  &  Sharpe  automatic  screw  machine  from 
%-inch  round  bar  stock.  The  order  of  operations  is :  Feed 


CARTRIDGE  CASE  MANUFACTURE 


209 


stock  to  stop,  form  and  bore,  ream  small  hole,  thread  and 
cut  off,  burr  in  the  burring  attachment.  The  stock  is  ro- 
tated at  2400  R.  P.  M.  for  forming  and  at  2400  R.  P.  M.  for 
threading.  The  production  is  400  per  hour.  The  second 
operation  is  slotting,  which  is  accomplished  in  a  National- 
Acme  screw  slotting  machine  as  shown  in  Fig.  166 ;  the  pro- 
duction is  about  800  per  hour.  The  third  operation  is  drill- 
ing, which  is  accomplished  in  a  Leland-Gifford  high-speed 
drilling  machine  as  shown  in  Fig.  167.  The  drill  used  is 
size  No.  55  (0.052  inch)  and  is  operated  at  10,000  R.  P.  M. 
An  indexing  fixture  is  used,  and  it  requires  three  indexes 
to  complete  the  drill- 
ing. The  production 
is  400  per  hour.  The 
fourth  operation  is  in- 
specting. 

Making  the  Plug — 
The  plug  D,  Fig.  164, 
is  also  made  on  a  No. 
00  Brown  &  Sharpe 
automatic  screw  ma- 
chine from  %-inch 
round  bar  stock.  The 
order  of  operations  is : 
Feed  stock  to  stop, 
form  and  groove, 
thread,  cut  off,  burr 
with  burring  attachment.  The  spindle  speed  is  2400  R.  P.  M. 
and  the  production  is  600  per  hour.  The  three  fire  holes  are 
also  drilled  in  the  Leland  &  Gifford  high-speed  drilling  ma- 
chine shown  in  Fig.  167,  using  an  indexing  attachment. 
The  drill  is  operated  at  10,000  R.  P.  M.,  and  400  per  hour 
are  turned  out.  A  different  jig  is  used  for  drilling  the  plug 
from  that  used  for  the  anvil.  In  the  case  of  the  plug,  the 
holes  are  drilled  parallel  with  the  axis,  and  in  the  anvil 
at  an  angle  of  26  degrees  with  the  axis.  The  percussion 
cap  E,  Fig.  164,  is  made  in  a  small  punch  press  in  one  oper- 
ation, a  combination  blanking  and  cupping  punch  and  die 


Fig.  167.     Drilling   Fire-holes  in  Anvil   In  a 

Leland-Gifford    High-speed    Drilling 
Machine 


210  CARTRIDGE  CASE  MANUFACTURE 

being  used.     The  soft  copper  ball  G  is  a  standard  product 
of  the  ball  manufacturers. 

Assembling  and  Loading.  —  Up  to  the  present  time,  few 
of  the  manufacturers  that  have  taken  orders  for  primer 
parts  are  assembling  and  loading  them.  This  delicate  and 
somewhat  dangerous  operation  is  generally  handled  in  the 
government  arsenals  or  in  cartridge  factories  regularly  de- 
voted to  this  work.  Manufacturers  that  have  taken  orders 
for  complete  rounds  of  ammunition,  however,  may  be  called 
upon  to  handle  this  work  in  the  future.  Before  the  primer 
can  be  assembled,  the  copper  cap  E,  Fig.  164,  must  be 
charged.  This  is  made  on  a  double-action  punch  press,  and 
is  blanked  and  cupped  in  one  operation.  After  cupping,  it 
is  cleaned,  dried  and  then  coated  with  a  varnish  containing 
the  following  constituents:  Finest  orange  shellac,  20  per 
cent ;  spirits  (methylated) ,  80  per  cent.  The  next  operation 
is  charging  the  cap  with  1.2  grain  of  the  following  explo- 
sive composition : 

Parts   (by 
Constituents  weight) 

Sulphide  of  Antimony 18 

Chlorate  of  Potash 12 

Glass   (ground)    

Powder  (mealed)  1 

Sulphur 1 

For  charging,  the  caps  are  held  on  one  plate,  and  a  sec- 
ond plate  called  a  "charger,"  having  the  same  number  of 
holes  as  the  cap-plate,  is  located  over  the  caps,  and  the  ex- 
plosive charge  held  in  the  plate  is  deposited  in  the  cap. 
The  cap-plate  is  then  taken  to  a  fulminate  pressing  press, 
where  the  charge  in  the  cap  is  compressed  by  means  of 
punches  under  a  pressure  of  800  pounds.  The  next  step  is  to 
lacquer  sheets  of  tin  foil  on  one  side  with  the  following  com- 
position: Seedlac,  10.52  per  cent;  turmeric,  5.26  per  cent; 
spirits,  methylated,  84.22  per  cent.  Disks  are  then  cut  out 
from  this  tin  foil  and  pressed  into  the  cup  under  400  pounds 
pressure,  the  lacquered  side  outward.  The  primer  cup  is 
then  coated  with  the  same  varnish  as  that  used  on  the  cap 
previous  to  charging.  The  cap  is  now  coated  externally 


CARTRIDGE  CASE  MANUFACTURE  211 

with  Pettman's  cement  which  is  composed  of  the  following 
ingredients : 

Ingredients  Per  Cent 

Gum  Shellac 18.18 

Spirits,  methylated 19.39 

Tar,  Stockholm   12.12 

Red,  Venetian   50.31 

The  primer  is  now  ready  for  loading,  and  the  first  part 
to  be  assembled  is  the  cap  E.  Before  this  is  placed  in  the 
body  A,  however,  the  pocket  in  the  latter  is  coated  with  Pett- 
man's cement.  The  parts  are  then  put  in,  in  the  following 
order  (see  Fig.  164)  :  Cap  E,  anvil  C,  soft  copper  ball  G, 
and  brass  plug  D.  Plug  D  is  locked  in  place  by  three  small 
punch  blows,  after  which  the  fire  holes  are  covered  with  a 
paper  disk  /  that  is  secured  with  Pettman's  cement.  The 
primer  cavity  is  now  filled  with  R.  F.  G.2  powder,  and  the 
brass  closing  disk  B,  with  paper  disk  H  attached  to  the 
inner  surface  by  Pettman's  cement,  is  then  put  in  place. 
This  is  finally  held  in  place  by  spinning  over  the  edge  of  the 
primer  body,  as  shown  in  Fig.  164.  The  last  operation  is 
to  coat  the  outer  surface  of  disk  B  with  Pettman's  cement, 
after  which  the  primers  can  be  turned  over  to  the  inspectors. 


CHAPTER  XI 
MAKING  CASES  WITH  BULLDOZERS  AND  PLANERS 

THE  manufacture  of  cartridge  cases  is  usually  carried  on 
by  means  of  power  presses  of  the  crank  and  flywheel 
type,  but  many  manufacturers  have  had  to  resort  to  other 
methods  of  handling  the  work.  In  one  case,  where  car-shop 
equipment  is  used  for  this  work,  all  the  cupping,  redrawing, 
and  tapering  operations  are  accomplished  on  bulldozers  and 
frog  and  switch  planers  which  have  been  fitted  up  for  this 
purpose.  The  only  special  machine  that  had  to  be  pur- 
chased to  complete  the  cartridge  case,  with  the  exception 
of  the  machining  operations,  was  a  hydraulic  heading  press. 
The  order  of  cupping  and  redrawing  operations  is  shown 
in  Fig.  168,  and  in  Table  VIII,  which  includes  all  the  data- 
machines  used,  production,  scleroscope  readings,  etc. 

Cupping.  —  In  this  plant,  the  blank  is  obtained  of  the  cor- 
rect size  and  thickness,  and  in  the  annealed  condition.  The 
first  operation,  therefore,  is  cupping,  as  shown  at  A,  Fig. 
168  and  in  Fig.  169.  For  this  work,  a  Niles-Bement-Pond 
bulldozer  is  used.  The  die  is  held  on  the  cross-head  and 
the  punch  on  a  fixture  attached  to  the  bed  of  the  machine. 
This  particular  machine  is  fitted  up  for  accomplishing  both 
the  cupping  and  first  redrawing  operations,  the  punch  shown 
at  A  performing  the  cupping  and  that  at  B  the  first  redraw- 
ing. In  this  way,  two  men  can  operate  the  machine  and 
thus  turn  out  a  cup  and  perform  the  first  redrawing  opera- 
tion at  each  stroke  of  the  machine.  A  lubricant  known  as 
"Viscosity"  and  made  by  the  Cataract  Refining  Co.  is  used 
for  lubricating  the  die  and  punch. 

Annealing.  —  Following  the  cupping  operation,  the  cases 
are  annealed  in  a  Quigley  oil  furnace,  as  shown  in  Fig.  170. 
The  cases  are  held  in  a  sheet-iron  pan  having  a  wire  bottom 
and  are  brought  to  the  furnace  on  a  truck,  as  shown,  the 

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CARTRIDGE  CASES 


to  the  right  of  the  illustration.  Here  the  pan  is  again  picked 
up  by  an  air  jack  and  dipped  in  the  weak  sulphuric  acid  solu- 
tion used  in  removing  the  scale.  Following  this,  the  cases 
are  immersed  in  a  hot-water  solution. 


Fig.  169. 


Performing  Cupping  and   First   Redrawing  Operations 
on    a    Niles-Bement-Pond    Bulldozer 


Fig.   170. 


Annealing   Cartridge  Cases  in   a   Quigley  Oil    Furnace 
for   Thirty-five    Minutes 


First,  Second,  and  Third  Redrawing  and  Indenting  Opera- 
tions. —  After  annealing  and  washing,  the  cases  are  taken 
back  to  the  Niles-Bement-Pond  bulldozer,  shown  in  Fig. 


CARTRIDGE  CASES  217 

169,  and  the  first  redrawing  operation  is  performed  as 
previously  described.  They  are  again  annealed,  washed, 
etc.  Following  this,  the  second  redrawing  operation  is  per- 
formed on  a  Williams  &  White  bulldozer,  where  the  punch 
and  die  are  held  in  the  same  manner  as  for  the  first  redraw- 
ing operation.  Annealing,  washing,  etc.,  follows  the  second 
redraw.  The  head  end  of  the  cartridge  case  is  now  indented 
in  a  Williams  &  White  bulldozer,  where  the  base  end  is 
formed  to  the  shape  shown  at  D,  Fig.  168,  and  is  then  given 
the  third  redrawing  operation  without  annealing  as  shown 
in  Fig.  172.  Here  the  operator  removes  the  case  from  a 


Fig.   171.     Immersing  Cases  in   Cooling  and   Pickling   Baths  following 

Annealing 

tank  which  is  filled  with  a  lubricant — "Viscosity" — and 
places  it  on  the  punch,  as  illustrated,  when  the  cross-head 
is  on  the  backward  stroke. 

Following  the  third  redrawing  operation,  the  case  is 
again  annealed,  washed,  etc.,  and  is  then  taken  to  the 
Williams  &  White  bulldozer,  where  the  fourth  redrawing 
operation  is  accomplished.  After  the  fourth  redrawing 
operation,  the  case  is  annealed,  and  then  taken  to  the  second 
indenting  operation.  This  is  accomplished  in  a  Williams  & 
White  bulldozer  at  the  rate  of  300  per  hour. 

At  this  point,  an  operation  is  performed  that  is  not  gen- 
eral practice;  a  14-inch  hole  is  drilled  through  the  primer 


218 


CARTRIDGE  CASES 


pocket.  In  attempting  to  form  the  head  of  the  cartridge 
case  with  the  primer  pocket  solid,  it  was  found  that  the 
metal  in  the  proximity  of  the  pocket  was  much  harder  than 


Fig.  172.     Third  Redrawing  Operation  on  Williams  &  White 
Bulldozer 


Fig.  173.     Performing  Fifth  Redrawing  Operation  on  a  Frog 
and    Switch    Planer 

at  the  rim.  This  is  just  the  reverse  of  what  is  required; 
in  other  words,  the  rim  must  be  much  harder  than  the 
center  of  the  head.  But,  a  hole  drilled  through  the  pocket, 
in  the  heading,  allows  the  metal  to  flow  freely  to  the  center, 


CARTRIDGE   CASES 


219 


Fig.  174.     Heading  Cartridge  Cases  on  a  C.   P.   R.   Heading 
Machine 


Fig.  175.     Mouth-annealing  Cartridge  Case  in  an  Improvised 
Annealing    Furnace 


220 


CARTRIDGE  CASES 


and  thus  prevents  "packing"  and  subsequent  hardening. 
Following  the  drilling  of  the  hole  in  the  primer  pocket,  the 


Machinery 


Fig.  176.     Diagram  showing  Dies  and  Heading  Tools  used  in 
Machine   shown    in    Fig.    174 


Machinery 


Fig.  177.     Dies  used  for  First  and  Second  Tapering  Operations 
on  Cartridge  Case 

case  is  taken  to  a  Toledo  case  trimmer,  where  the  open  end 
is  trimmed,  removing  the  ragged  edge  from  the  mouth  of  the 
case. 


CARTRIDGE  CASES  221 

Fifth  and  Sixth  Redrawing  Operations.  —  The  fifth  and 
sixth  redrawing  operations  are  handled  on  a  frog  and  switch 
planer,  as  shown  in  Fig.  173.  The  entire  cross-rail  has 
been  removed  and  a  large  casting  A,  serving  as  a  punch- 
holder,  is  fastened  to  the  uprights.  The  redrawing  punch  B 
is  therefore  held  stationary.  The  redrawing  die,  on  the 
other  hand,  is  held  in  a  holder  retained  on  casting  C  bolted 
to  the  planer  table.  The  method  of  operating  is  to  place  the 


Fig.   178.     Hand-reaming   Primer   Pocket  in   Head   of  Cartridge 

Case 

case  on  the  punch  when  the  planer  table  is  on  the  return 
stroke.  The  punch  and  die  is  lubricated  by  a  lubricant 
held  in  box  D,  which,  of  course,  travels  with  the  die.  The 
case,  in  being  forced  through  the  die,  slides  down  a  trough 
into  a  box. 

After  the  fifth  redraw,  the  case  is  annealed,  washed,  etc., 


222 


CARTRIDGE  CASES 


and  is  then  given  a  sixth  redraw  which  is  accomplished  in  a 
similar  manner  to  the  fifth.  The  mouth  of  the  shell  is  again 
trimmed  on  the  Toledo  case  trimmer  and  from  here  is  taken, 
without  annealing,  to  the  heading  press. 

Heading.  —  The  heading  operation  is  now  performed  in 
the  350-ton  press  shown  in  Fig.  174,  which  is  built  by  the 
Canadian  Pacific  Railway.  This  machine  is  provided  with 

a  table  of  the  indexing 
type  which  carries 
four  sets  of  dies, 
shown  in  detail  in  Fig. 
176.  In  heading,  the 
case  is  given  two 
blows;  the  first  is  de- 
livered by  punch  A, 
which  fills  in  the  prim- 
er pocket.  Punch  B, 
which  is  held  on  a  rod, 
as  shown  in  Fig.  174, 
is  then  placed  over 
the  case  and  a  flatten- 
ing blow  is  delivered. 
While  these  opera- 
tions are  being  per- 
formed, the  case  is 
supported  by  punch 
C,  Fig.  176. 

Mouth-annealing  and 
Tapering.  —  The  next 
operation  is  mouth- 
annealing,  which  is  accomplished  in  the  simple  furnace 
shown  in  Fig.  175.  It  comprises  a  stand  which  supports 
an  air  drill,  a  spindle  A,  fitted  into  the  driving  socket  of 
the  drill,  and  a  table  attached  to  this  as  shown.  The  case 
is  supported  on  this  table  and  rotated  by  the  air  drill ;  the 
annealing  is  done  with  an  oil  burner.  The  case  is  allowed 
to  rotate  for  thirty-five  seconds  and  is  heated  to  a 
temperature  of  800  degrees  F.  (427  degrees  C.)  for  a  dis- 


Fig.   179.     Testing    Hardness  of  Cartridge 
Cases  with   Scleroscope 


CARTRIDGE  CASES 


223 


tance  of  about  from  41/2  to  5  inches  from  the  mouth  of  the 
case. 

After  mouth-annealing,  the  cases  are  allowed  to  cool  off 
in  the  air,  and  when  cool  are  taken  to  a  Williams  &  White 
bulldozer.  Two  tapering  operations  are  necessary  to  bring 
the  case  to  the  correct  shape  and  size.  The  dies  used  for 
this  purpose  are  shown  in  Fig.  177.  The  first  tapering  die, 
shown  at  A,  is  made  in  three  pieces.  For  the  first  taper- 
ing, the  mouth  of  the  shell  is  not  supported,  as  the  reduction 
is  carried  along  the  entire  body.  In  the  second  tapering, 
however,  the  reduction  at  the  mouth  is  greater  and  necessi- 
tates using  a  supporting  bushing  a,  as  shown  at  B. 

Machining  Head  and  Mouth  Ends  of  Case.  —  Following 
the  tapering  opera- 
t  i  o  n  s  ,  the  cartridge 
case  is  taken  to  the 
machining  department 
where  a  series  of  op- 
erations is  performed, 
on  the  head  and  mouth 
ends,  on  a  Bullard  fac- 
ing, chamfering,  and 
trimming  machine. 
The  order  of  opera- 
tions is :  Rough-drill 
and  counterbore,  face, 
trim,  and  chamfer 
head,  finish-chamfer 
and  face,  under-cut 
primer  seat,  finish- 
counterbore,  tap  with 
mouth. 

The  case  is  now  taken  to  a  special  reaming  fixture,  shown 
in  Fig.  178,  where  the  primer  pocket  is  finish-reamed. 
Hand  tapping  of  the  primer  pocket  follows  this  and  is  ac- 
complished in  a  similar  fixture.  The  case  then  passes 
through  a  series  of  inspection  operations,  consisting  in  gag- 
ing the  diameter  and  thickness  of  the  head,  depth,  diame- 


Machinery 


Fig.  180.     Diagram  showing   Representative 

Scleroscope   Reading  taken  on   Head  of 

a  Cartridge  Case 


collapsing  tap,  trim  and  chamfer 


224  CARTRIDGE  CASES 

ter,  etc.,  of  the  primer  pocket;  over-all  length,  diameter 
of  mouth,  etc.  Another  inspection  is  looking  through  the 
case,  from  the  head  end,  to  detect  whether  any  free  spelter 
is  present  or  not.  The  cartridge  case  is  then  stamped  on 
the  head  end  in  a  Noble  &  Westbrook  stamping  machine. 
This  finishes  the  machining  and  inspection  operations  on 
the  case. 

Testing  for  Hardness.  —  The  hardness  of  the  metal  is 
tested  before  and  after  each  annealing  and  redrawing  oper- 
ation, and,  for  this  purpose,  the  scleroscope  is  used.  Fig. 
179  shows  an  inspector  taking  a  series  of  readings  on  the 
head  of  the  cartridge  case.  About  one  per  cent  of  the  daily 
production  is  inspected  in  this  manner,  and  Fig.  180  shows  a 
representative  reading.  The  body  of  the  case  is  also  tested 
for  hardness  at  the  points  indicated  in  the  illustration  ac- 
companying Table  VIII.  This  table  also  includes  the  sclero- 
scope readings  obtained  before  and  after  every  annealing 
and  redrawing  operation.  For  taking  a  reading  on  the 
body  of  the  case,  it  is  placed  on  the  horn  A,  Fig.  179.  Final 
inspection,  packing,  etc.,  finishes  the  operations  on  the  case. 


CHAPTER  XII 
COST  OF  MUNITIONS  OF  WAR 

At  this  time  when  the  principal  nations  of  Europe 
are  at  war  and  the  question  of  increasing  the  defenses  of 
the  United  States  is  being  agitated,  a  few  figures  on  the 
cost  of  guns,  etc.,  will  be  of  interest.  The  following  data 
on  the  cost  of  guns,  howitzers,  mortars,  mountings,  car- 
riages, projectiles,  powder  charges  and  fuses  were  fur- 
nished by  the  ordnance  departments,  Washington,  D.  C.,  and 
are  therefore  authoritative: 

3-inch  field  gun $     1,825.00 

4.7-inch  field  gun 4,650.00 

4.7-inch  howitzer 2,150.00 

6-inch  howitzer 3,325.00 

6-inch  seacoast  gun 6,700.00 

12-inch  seacoast  mortar 11,000.00 

14-inch  seacoast  gun 55,000.00 

The  costs  of  carriages  and  mountings  for  seacoast  guns 
are: 

15-pounder  barbette   $     5,000.00 

5-inch  barbette 13,500.00 

6-inch  barbette 14,000.00 

6-inch  disappearing 24,000.00 

10-inch  disappearing 37,000.00 

12-inch  disappearing 65,000.00 

14-inch  disappearing 85,000.00 

16-inch  disappearing 130,000.00 

12-inch  mortar 18,000.00 

The  cost  of  artillery  carriages  of  the  mobile  or  trans- 
portable type  is  as  follows: 

3-inch  field  gun  carriage $     2,181.00 

3.8-inch  howitzer  carriage   8,500.00 

225 


226  COST   OF   MUNITIONS 

3.8-inch  gun  carriage $  5,462.00 

4.7-inch  howitzer  carriage 10,562.00 

4.7-inch  gun  carriage 4,361.00 

6-inch  howitzer  carriage 14,147.00 

If  manufactured  in  the  government  plant,  a  round  of 
ammunition  costs  approximately  as  given  in  the  following, 
but  when  purchased  from  manufacturers,  the  cost  is  higher. 

3-inch  field  gun $  10.00 

4.7-inch  gun    28.00 

6-inch  howitzer   43.00 

3-inch,  15-pounder 15.00 

6-inch 60.00 

12-inch  gun 500.00 

12-inch  mortar 300.00 

14-inch  gun 800.00 

16-inch  gun    1,200.00 

The  smokeless  powder  for  seacoast  ammunition  costs  53 
cents  a  pound  when  purchased  and  somewhat  less  when 
manufactured  by  the  government. 

Following  are  data  on  the  cost  of  naval  guns,  carriages, 
etc.: 

3-inch  naval  gun $     3,973.00 

5-inch  naval  gun 7,600.00 

7-inch  naval  gun 21,850.00 

12-inch  naval  gun 72,820.00 

14-inch  naval  gun 112,000.00 

3-inch  gun  mounting 2,500.00 

5-inch  gun  mounting 9,860.00 

7-inch  gun  mounting 11,000.00 

12-inch  gun  mounting 52,357.00 

14-inch  gun  mounting 44,000.00 

3-inch  projectile 1.97 

5-inch  projectile 8.72 

7-inch  projectile 62.00 

12-inch  projectile 165.00 

14-inch  projectile 400.00 

3-inch  gun  powder  charge 2.12 

5-inch  gun  powder  charge 9.40 


COST   OF   MUNITIONS  227 

7-inch  gun  powder  charge $          30.60 

12-inch  gun  powder  charge 147.40 

14-inch  gun  powder  charge 201.40 

3-inch  gun  fuse 0.80 

5-inch  gun  fuse 1.45 

7-inch  gun  fuse 4.80 

12-inch  gun  fuse 4.80 

14-inch  gun  fuse 4.80 

The  cost  of  a  torpedo  is  $8500  and  of  the  explosive  $350. 
A  navy  rifle  complete  costs  $20;  pistol,  $18.    The  navy 
pays  53  cents  a  pound  for  smokeless  powder  and  14  cents  a 
pound  for  black  powder. 

The  following  data  of  costs  of  armor  plates  and  shells 
have  been  compiled  from  bids  of  private  concerns : 

4-inch  naval  gun  shells $     9.50 

5-inch  naval  gun  shells 12.00 

14-inch  naval  gun  shells 415.00 

7374  tons  armor  plate,  per  ton 435.00 

401  tons  armor  plate,  per  ton 486.00 

290  tons  armor  plate,  per  ton 466.00 

63  tons  armor  plate,  per  ton 376.00 


INDEX 


PAGE 

Adapter,  machining   177 

Ammunition,  fixed    23 

Annealing  cartridge  cases 184,  212 

Anvils  for  primers,  making 208 

Armor-piercing  shells,  forging 52 

Armor-piercing  projectiles    9 

Assembling   fuses    .' 178 

Assembling  primers 210 

Banding  howitzer  shells  , 143 

Benzol 39 

Blanking  cartridge  cases 181 

British  18-pounder  shell  • .  5 

machining  53 

British  detonating  fuse,  manufacture  of 163 

British  high-explosive  fuse  17 

pellet  charge  19 

British  howitzer  shells  127 

British  shell  blanks,  forging  42 

Bulldozers  used  for  making  cartridge  cases. 212 

Capped  projectiles  11 

Cartridge  cases,  manufacturing  with  bulldozers  and  planers. 212 

manufacture  181 

Center  plug  for  fuses,  machining 179 

Chlorate  of  potash,  American  composition 28 

British  composition  30 

Chlorates  40 

Combination  primers  30 

Concussion  fuse 15 

Conveying  apparatus  for  rapid  handling  of  shells 161 

Copper  bands,  pressing  on  and  forming 78,  120,  135 

Cordite  37 

Cost  of  munitions  of  war 225 

Cupping  cartridge  cases 181 

Delay-action  fuse  shells 4 

Detents,  machining  176 

229 


230  INDEX 

PAGE 

Detonating  fuse,  manufacture  of 163 

Disks  for  primers,  making 208 

Dunnite    5,  40 

Electric  primers   28 

Emmensite    38 

Explosives,  classification   32 

Fixed  ammunition  23 

Forging  high-explosive  shells  42 

French  75-millimeter  shell   7 

French  120-millimeter  shell,  inspection   123 

machining    100 

testing  for  strength  126 

Friction  primers  27 

Fulminate  of  mercury 40 

Fulminates 40 

Fuses,   assembling    178 

delay-action    4 

British  high-explosive  17 

British  high-explosive,  manufacture  of 163 

Russian   high-explosive    20 

general  description   13 

Gaging  cartridge  cases   198 

Gas  plugs 77 

Gaine  parts,  machining   178 

Grinding  high-explosive  shells   154 

Guncotton,   manufacture   of    34 

Guncotton  press 35 

Gunpowder 33 

Hardness  testing  of  cartridge  cases 204,  224 

Hardness  testing  of  high-explosive  shells 152 

Heading  cartridge  cases    192 

Heat-treating  Russian  shells   81 

High-explosives    38 

High-explosive   shells,   development 1 

forging   42 

types   2 

Howitzers,  loading   24 

shells,   machining    127 

Indenting   cartridge   cases 186,  216 

Inspecting  British  shells . .  75 


INDEX  231 

PAGE 

Inspecting   cartridge   cases 198 

Inspecting  French  shells 123 

L  oading  primers   210 

Lyddite     38 

Machining  British  18-pound  shells 53 

Machining    cartridge    cases 197,  223 

Machining  French  shells   100 

Machining  howitzer  shells    127 

Machining  Russian  shells   80 

Machining  Serbian   shells 88 

Maximite   38 

Melenite  38 

Mortars,  loading   24 

Munitions  of  war,  cost  of 225 

N  itrobenzole 38 

Nitronaphthaline 38 

O  give,  machining  , 92 

P  ellet,  machining  percussion  176 

Percussion  fuse,  American 15 

Percussion  pellet,  machining  176 

Percussion  primers  28 

Picric  acid  39 

Planers  used  in  making  cartridge  cases 212 

Plugs  for  primers,  making 209 

Plugs,  gas 77 

Powder,  black  33 

smokeless  34 

Primers,  for  cartridge  cases 27 

making  204 

Projectiles,  armor-piercing  9 

capped 11 

Pyrocellulose,  manufacture  of  34 

Redrawing  cartridge  cases 186,  216 

Russian  3-inch  shell   7 

Russian  high-explosive  fuse 20 

Russian  shell  blanks,  forging 46 

Russian    shells,    machining 80 


232  INDEX 

PAGE 

Serbian  shells,  machining  88 

Shell  fillers    38 

Shell  manufacture,  tools  and  devices  for 145 

Shimose    38 

Smokeless  powder    34 

Testing  cartridge  cases 198 

for  hardness    •  • 204,  224 

Testing  French  shells   126 

Testing  hardness  of  shells 152 

Tools  and  devices  for  shell  manufacture 145 

Trinitrotoluol    39 

Varnishing   shells 65,  159 

Serbian    shells 95 


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